I have fixed my Rodeo 3:1 transfer case by swapping in the Lo shifter fork and slide gear (don't know the actual name) from a spare transfer case I picked up at a junk yard. Since my 4lo is working again it has taken the pressure off for getting the H3 stuff installed so no rush now.

For clarity I will refer to the Trooper trans as the AR5 and the Hummer H3 as the MA5

I've been putting a list together of parts I'll need and there are few options on how to proceed and obstacles to completion as I see it:

1) Use the bell-housing and the clutch throw-out bearing fork assembly from my AR5 and that lets me use the original pressure plate.
However, it complicates the swap for anyone in the future because an AR5 is needed to complete the kit.

2) Use the input shaft that is currently on the MA5 which has a different spline count, 26 vs 24 for the AR5, length and bearing diameter. The H3 input shaft is a little bit shorter, not much but needs to be accounted for and the bearing surface diameter is smaller.
Pilot bearing for AR5 and MA5
AR5 MA5
OD 1.5748” 40mm OD 1.70” 43.3mm
ID 0.6693” 17.0mm ID 0.59” 15mm
Thick 0.7874” 20mm Thick 0.51” 13mm
Needs 1.5748” 40mm x 0.59 15mm x 0.7874” 20mm to match the outside diameter of the Trooper crank surface and the inside diameter of the H3 input shaft surface.
I believe a clutch for an 82-92 Camaro 5.0L will work but this needs to be confirmed.

3) Swap the AR5 input shaft into the MA5.
This would allow for all the stock Isuzu AR5 pieces to be reused. Again this complicates the swap for anyone in the future because an AR5 is needed to complete the kit. I'm also assuming the input shafts can be swapped and this assumption can probably only be confirmed by disassembly of both transmissions. The input shaft cannot be removed with the trans assembled as it has to come out from the inside.

4) Use the bell-housing and clutch throw-out piston assembly that comes with the MA5. This would hopefully negate the need for a spare AR5 donor however a usable matching push style pressure plate would need to be sourced along with any hydraulic line/linkage differences. I would prefer this approach but I'm not sure about the unknown obstacles to accomplish this.

5) Due to the larger size of the transfer case a custom clocking ring will likely be needed. How far down will the TC hang in order to clear the passenger side torsion bar? If it is too far this could kill the project altogether as it would be too susceptible to damage while wheeling.

6) Is the MA5 speed sensor compatible with the Isuzu setup?

7) What else am I not considering?