I thought that the 'Vic wasn't a roller, but I've been wrong before. I thought that the 'Vics used the 15426378 firing order, like the trucks and older 302s. So I assumed non-roller. We need FoxChassis to rule on this.
The E7TE heads came on all '87 and up 'Stang H.O.s. The '86 motor was a one-year-only deal in the Mustang. The heads are different (most people say not as good as the ones before and after) as are the pistons, which are taller and can cause clearance problems with other head/cam combos. I've heard that the Speed Density cam in the '86 works wonders in later Mass Air motors, and is the same as the '93 Cobra. The '85 and earlier heads are not too far off the mark of the E7TEs, but you really want something like any of the GT40s, or better. Stockers will still get you around town in front of many other cars.
If you are gonna use the 'Vic as a donor, I highly recommend a schematic for both cars, as the harnesses will be different. You'd need an FI fuel delivery system from a 'Stang (tank, pump, lines). With an automatic computer, you don't want to connect the neutral safety switch circuit to the manual car - just use a toggle switch. The car has to be in neutral to give out error codes, and to properly learn to Idle. I'd get the 'Vic, yank the motor, computer, and all related harnesses. I'd keep the tranny too. The best thing you could do though, is get the computer and all of the wiring from an '89-'93 5.0 5 speed stang. It's alot of stuff - including the clutch pedal switch which ties into the neutral switch circuit, but it's worth it IMO, because the car can be serviced by anyone wo knows 'Stangs. Engine electrical systems which consist of cobbled together harnesses can be hard to troubleshoot for anyone - sometimes even the person who put it together. If you were to end up with a 15426378 motor, and a 13726548 computer and wiring, you could still change the injector order and have it work, just get a spare injector harness to butcher.