I am not sure who makes an aftermarket tcu for the 722.6, but I know they are out there and I'm sure someone else can chime in with those details!

As the swap goes, the shifter itself is different, but easy to swap, you may need a harness if the aftermarket tcu doesn't have one already. The shift rod maybe different or not, not 100% sure.

You will need to use the flex plate that you have, since the crank sensor pickup signals are different between 96'-97'.

The 3.67 diff off a C240 also doesn't have axle flanges, I am not sure if the w202 stub axles can to snapped in place, however a 203 uses different style axles without the 6-bolt flanges.