Its been many years since I pulled a trans without the engine. Are motor mounts enough to support the engine, or do I need to fabricate a support for the rear of the engine?

You could wrap a rag around a short piece of appropriate size wood block and set it between oil pan and centerlink usually.

Assuming the car will not be moved?

Blocks of wood
Jack
car stands

If the exhaust is still on it, wrap straps around the exhaust pipes, and then around the torsion bars.

i usally unbolt the trans from the cross mount then let it drop a couple o inches then block the engine with 4x4 or 2x4 wood then remove the trans.it makes it eaisier to put back in IMO, your results may vary.

The factory style motor mounts should be able to hold the motor up, but I'd use a small block of wood b/t the oil pan and drag link to hold it up.
If the exhaust system is still hooked up, then you really don't need to block of wood. The motor mounts hold the weight of the motor, the exhaust will just keep it from trying to tip backwards.

I have to remove the trans in the 69 Dart this w/e. I always pop the distributor cap off too since it will get close to the firewall on an A body. I used the 73 up spool mount K frame and a 2x4 setting on the drag link is almost perfect when the trans is removed.

Small jack out of daily driver and a block of wood.

That's how I do it; while the engine mounts might hold the engine, you'll stress them past their normal limits...they fail often enough as it is.

A few years back I came up with a simple support to shift the pressure onto the rails and block. Less chance of distorting the pan this way. It's set up so it can be used with the jack as well as a long term support with jack stands or steering link.

I just keep it simple.
Bolts (seen screw drivers used) through the lower mounting holes in the block and a 2X4, even a broom handle has worked, across the torsion bars. Rest bolts on top of 2X4 and everything is solid.
Car can be moved and the motors stays put.

My solution also... with non-hydraulic jack so it does not creep down. It is possible to rig supports between the T bars also... always with a block of wood between the back of the oil pan any any steel supporting it.

I just use the bridge crane to hold the engine up while I'm working on the trans.

Show-off!!LOL

Joe