You will need motor mounts, trans should work (5 speed I take it) but you would need a bell housing off a pre 96 5.0 Stang. Emissions are subjective you can’t just say will it pass? A 351 does not produce a certain amount of emissions. Every engine is different it depends on how you want to build it. If you don’t have a bunch of cash to put into it to do it right it probably wont pass. I.E. you can’t go carbed and pass. You cant go huge cam, compression, and heads and pass.
No offense you don’t seem to be familiar with Stangs and I’m not sure I would try it then. A little history though. The car has the same frame (unibody) as the 79-2004 Stangs. The engine bays have been basically the same dimensions and look on all years. This frame readily accepts 289/302/351W engines which are the same basic size on the outside. They actually are a bit smaller than the 4.6 due to the cam in block layout (pushrod) versus the SOHC of the 4.6 (281 cubic inch).
There aren’t many benefits to the swap if you don’t have the cash to do it right. You would need a wiring harness for a 5.0 car, a F.I. setup for a 351, the engine itself, flywheel and clutch, all the serpentine drive on the front, bell housing, and exhaust.