TCU TurboLamik

In TunerPro you can set what input you wish to use and what voltage level the threshold is considered 'on'. Also you can invert that meaning if the brake switch is on when brake is off you can set the input according.

The TCU can output gear position either via CAN bus or as an analog voltage signal (0–5 V).

Wheel speed output from the TCU is configurable to any tooth count required by the dash and is provided through an analog output. This signal is a 0–5 V square wave only. If the dash requires a sine-wave ...

My take is that you need to build the transmission for the application—meaning the clutch materials and hard parts should match what you expect it to do. If you’re building a hot rod that you occasionally drive to work, almost any of them will work just fine.

I’ve had 50-series units hold torque ...

If you are in 'normal' mode on the shifter the program value won't change. You need to be in sport or manual mode to change p number

You need to get with support on this, you'll need a file from them. If the backplane you currently have is only 10pin it will not work. Also the 75 is a different valve body that will require an 8hp45 - 70 backplane. There are a few other differences like solenoid phasing which can be addressed in ...

Unfortunately the TCU can't run any gauges. It can run an overtemp light but no actual gauges.
There is a small display that can be connected directly to the TCU for basic data but that would be about it.

I guess I don't fully understand the question because I don't know what specifics you're looking for and what ecu or display will be used.
But yes CAN bus can be used, you mentioned LT4, so either your planning to run an OEM ecu or aftermarket either is not difficult to setup via CAN.
The tach is ...

What you're describing is absolutely doable. You would need to use a linear position sensor to get a voltage value for each gear selector position.
For example a typical B&M shifter for a hotrod uses a cable. You would replace the cable at the shifter with the linear position sensor. Then wire that ...

So to answer this you haven't provided enough info.
Is the motor turbo/supercharged? What is the idle vacuum when cold/hot in TunerPro with live data active? ( this is needed to setup the TQ tables ). What is the idle RPM when cold/hot?

Have you confirmed that RPM, MAP and TPS values are all ...

Settings shown are for rx only, to enable tx you will need to setup a can id that you can transmit to from the TCU.
Enter that id you have selected and then select what analogs your sending