SC2Mapster

Don't think it's possible to change the item type in a trigger, think the item class is hard coded into whatever you create in the data editor and can't be changed.
Tho I could be wrong.

Think you could make multiple versions of the same item each one as a different item class.

I had to do this to make it look like I'm walking on a light bridge,
Create pathing from one cliff to another cliff, place bridge.
This set the bridge at ground level instead of cliff level so set height property of doodad to 10.
Created region with the same dimensions as the bridge = Light Bridge Path.

Trigger
Any unit enters region Light Bridge Path
Set unit height = 10
Trigger
Any unit leaves region Light Bridge Path
Set unit height = 0

This may work on your map:
Added 4 regions surrounding Bridge Path region, 2 for ground 2 for cliff.
Boolean Variable: On Bridge[Array = # of players] = False

Trigger
Event any unit enters cliff region
Action - set variable On Bridge[triggering player] = True <<do the opposite for the enter ground regions>>

Trigger
Event - Any unit enters region Light Bridge Path
Condition - On Bridge[triggering player] = True
Action - Set unit height = 10

There is a flag Auto Cast On that is default to off for SCV - Repair
Target Filters section

Issue may be because repair bot your making is immobile. Think repair require the unit to move towards it's target before it gets activated since melee range.

Have you tried remaking science vessel ability Nano Repair? Edit it to drain minerals instead of energy somehow.
They have an auto cast for repairing machines similar to what medics do to bio units.

Messing around I added this to a Reaper and for ability target flag set Structure as allowed. Now reapers auto heal buildings as a SCV builds it.
Edit: Though this doesn't make the building be built any faster like I thought it would.

Looking thru the structure stats for base buildings I can't seem to find a building duration.
I want to be able to build in seconds instead of minutes.

I see a Stats - Repair Time but no Build Time

I tested your map, I changed movement from "Cliff Jumper2" to "Cliff Jumper" then the unit could jump.
Seems the duplicated value didn't copy everything required to jump cliffs.

Specifying item location is done when you create the Data type Item

Following the guide here
http://rpg-exploiters.com/guides-strategies/starcraft-2-galaxyedit-complete-hero-tutorial/

Need make in data editor:
<Speed Charm accessory example>
Button
Buff
Item <Object type = slot location>
Unit
Actor

I'm using this library for adding XP to unit if you implement Hero Levels behavior.
http://forums.sc2mapster.com/development/galaxy-scripting-and-trigger-lib/5069-library-add-experience-to-unit/

With it you could make a trigger:
Event - Unit - Any Unit uses Medic - Heal (Medic) at Generic1 - Any stage (Ignore shared abilities)
Actions:
Add Experience to Unit (10, (Triggering unit))

Adds 10 XP to healer each time heal is cast

Sounds like exactly what I have on my map.
My map locks the camera on the unit a Player owns

Trigger: Always Trigger
Event: Timer - Every 0.1 seconds of Game Time
Actions:
General - If (Conditions) then do (Actions) else do (Actions)
If
((Closest unit to Start Area in (Any units in (Entire Map) owned by player 1) is alive == true
Then
Camera - Apply camera object Rotation (Facing of (Closest unit to Start Area in (Any units in (Entire Map) owned by player 1))) for player 1 over .5 sec
Camera - Pan the camera for player 1 to (Closest unit to Start Area in (Any units in (Entire Map) owned by player 1)) over .5 sec
Else

Pan the camera action locks the camera on the player, don't make the duration less then .5 sec or camera with start having a choppy look to it when it follows their hero unit.

Placed in the If Alive condition because all units can revive on my map after 45 seconds for testing balancing of different areas, I may remove this once I complete the map.

Camera Rotation action I made to always point the camera the direction that the unit is looking, player is always looking at the back of the unit's head.

Not sure if ally with shared control allow your unit to go inside their bunker.
But wouldn't it be cool if several different players can go into the same bunker, not sure if that's even possible.

Any one know how to add attribute behavior to a unit?
Want player to choose Str Agi Stam or Int at level up and be applied via Dialog Menu.

I'm using this library for adding XP to unit if you implement Hero Levels behavior.
http://forums.sc2mapster.com/development/galaxy-scripting-and-trigger-lib/5069-library-add-experience-to-unit/

Thinking something similar is need to do what I want.
Not sure where in the data editor to start to create this.

What is the exact options I need to choose to create this event?
Event: Dialog - Any Dialog Item is used by Player Any Player with event type Clicked

I am not finding the Any Player in Function section or Preset section.
Was it listed in the Beta editor and not in the Current version?
A lot of the guides I've seen with pictures look different to the editor I have.

Edit:
Just copied the event from the Lost Viking arcade map from the campaign. I must be blind, no clue where the Any Player thing is at.
Think I'm understanding how dialog menus work now after viewing Blizzard's dialog code in the map.

Here is my code:

Global variables:
Stamina [Dialog Item]
Strength [Dialog Item]
Agility [Dialog Item]
Intellect [Dialog Item]

Trigger: Detect Level Up
Event: Any unit gain exp level
Action:
Create a Modal dialog
Set title = "Level Up"
Create button "Stamina"
Set Stamina = Last created dialog item
Create button "Strength"
Set Strength = Last created dialog item
Create button "Agility"
Set Agility = Last created dialog item
Create button "Intellect"
Set Intellect = Last created dialog item
Show last created dialog for Group of (Triggering Player)

Trigger: Menu button selected
Event: Any dialog item is used by Group of Player 1 type Clicked
Actions:
Switch (Used Dialog Item)
Case Stamina
Add 1 Stamina behavior to Triggering Unit from Triggering Unit
Case Strength
Add 1 Strength behavior to Triggering Unit from Triggering Unit
Case Agility
Add 1 Agility behavior to Triggering Unit from Triggering Unit
Case Intellect
Add 1 Intellect behavior to Triggering Unit from Triggering Unit
Dialog - Hide Last Created Dialog for All Players

Is the event in the 2nd trigger the correct way to detect when a button is pressed?
I did not see a Any Player function listed like shown in all the guides I seen that says set this to "Event - Any dialog item is used by Any Player type clicked"

Been struggling with this one trigger for over an hour.

I did not see this mentioned in the "WC3 like shared experience" post.

Are there any tutorial on how to display a variable to player?
Want to show everyone in my map their own Total Experience variable, based on amount show level too.

Here is my experience trigger on my map.
If there is a easier way to do this then what I got, love to hear about it.

Global Variable Total Experience (Real [4])
Global Variable Experience (Real)

Always running trigger
I have trigger move region Player 1 to closest unit owned by Player 1 every .01 game seconds

<<have this action listed 4 times for players 1 - 4; have a huge region called Shared Exp>>

Trigger: Give Exp
Event: Any unit dies
Local Variable: # of units
Condition: Triggering player == hostile
Action:
move region Exp Range to position of triggering unit
set variable Experience = triggering unit property Maximum Life
If: point - region Player 1 is in region Shared Exp
Then: # of unit = # of units + 1

<<repeat this If statement for each player>>

Set variable Experience = Experience / # of units

If: point - region Player 1 is in region Shared Exp
Then: Total Experience [1] = Total Experience [1] + Experience

<<repeat this If statement for each player>>

set variable Experience = 0

<<I haven't got to test this yet since I'm still in the process of creating puzzle areas and terrain on my map.>>