Use the inertia switch. If not, and there is an accident, it's pouring fuel onto the fire continually until the tank is empty. Let that sink in, if you are stuck inside the cab.....you are toast.
The SVO's harness is pretty simple. There are plenty of diagrams online so you can make heads or tails of it. Or it's also possible to buy a harness from ron francis I think. The only sensors you might not want to use would be the ACT and the KS (air charge temp sensor and knock sensor respectively). Almost nobody uses the knock sensor on the 2.3 turbo's. Why? The factory "slider" camshaft and followers are all worn out, lobes have a ditch in them. This causes a little bit of "noise" in the valvetrain which the knock sensor interprets as a "knock", thus retards the timing. Most of us just unplug the sensor and it will run fine. That part of the harness could be totally removed. The ACT isn't necessarily required but is a good idea to keep it if possible. EGR is another one that isn't necessarily needed, and if you remove the EGR system you can just cut the whole egr parts off of the upper intake and tap the holes for a pipe plug and you are done. If you remove the ACT, KS, and EGR, you will get codes and occasionally a check engine light, if you have one of those in your swap. It won't necessarily make the engine run worse; although the ACT does help it run "better" (safer) when no intercooler is used.
Fuel pump. The relay has constant power from the battery on one of the pins and then the wire from pin #22 (on PE catch code computer) is a ground. When you turn the key on, the computer grounds the pin which actuates the relay's coil, which then makes internal contact connecting +12 from batt and sends it to the fuel pump wire. The pin #22 is is correct for PE computer, but depending on which computer you have it may be a different pin. It's a really simple setup and it flat works, and works reliably, thus I suggest using it. You already have the mazda wiring in the car, so whichever wire goes to the +12v side of the fuel pump is the wire that connects to the ecu controlled fuel pump relay. There will be a second wire on the fuel pump for ground, and that obviously goes to ground.
In stock application (turbo 2.3 SVO) there are two fuel pumps. The in-tank pump is a low pressure pump that feeds a frame mounted high pressure pump. Ford used this setup on a lot of cars & trucks in the 1980's. Most just convert to single in-tank pump. But in doing so, we've also got to bypass the resistor, as there is one in-line with the in-tank pump's wiring to reduce the voltage going to the in-tank pump. The way the system works is that when you first turn the key on, the ecu grounds the pump relay and it primes the pumps for 2 seconds, then shuts them off. When you crank the engine, and while the engine is running, the ecu grounds the relay and KEEPS it grounded until you turn the key back off. It does not have a pressure sensor to sense "priming" at all, it just primes automatically without actually knowing what the pressure is-it assumes that it's 40 psi. The factory pump also has a check valve in it to keep pressure from dropping off after you turn the key off. Or that's the way it's supposed to work...sometimes the check valve doesn't work quite right and can cause 0.5 second (give or take a minute) cranking time. That's all the "prime" function does, reduces cranking time.
People get confused on the OEM resistor for the in-tank pump. All it does is reduce the voltage going to the in-tank pump so that it doesn't over-power the frame-mounted pump. One can remove the resistor wire, remove the frame-mounted pump and insert a fuel filter in the pump's place, which applies +12v to the in-tank pump, and the in-tank will support the EFI engine by itself. BUT it doesn't have a huge volume, and by now they're all worn out, thus most replace them with a new walbro 190 liter/hour or 255 liter/hour 5.0 Mustang pump. It bolts right in. That may not apply to your truck but that's what is most common; or at least most talked about. I think the T-birds also had dual pumps from the factory similar to the Mustangs, and same thing with those. In fact a lot of Fords in the 1980's and 1990's had dual pumps (in tank + frame mounted). Trucks especially up to about 1992.
I've heard of people just using the ground from pin 22 to ground the pump directly without a relay but the computer won't last long with that method. A relay MUST be used.
Again some of the turbo computers use different pin locations so you will want to use the pinout for whatever computer you have. If it's a 85.5-86 SVO you will probably have a PE computer which is what I referenced above. If you have a 84 SVO computer, it's likely to be a ZBA or TE. I 85's were TJ or PJ. Thunderbirds were LB3, LA3, LA2, etc then there were Merkur XR4Ti computers, PK, etc. Again some of the ecu's pins are different between them so you will want to know for SURE which computer you have, then download the correct pinout for it. The PE makes the most power but the LA3 is the most common-and has a faster processor and MUCH better cold-start strategy; although by today's standards, it's a train wreck. Yes it is possible to run a 87-93 Mustang 5 speed V8 computer, but you will have to buy a quarterhorse, insert it into the J3 port, and then tune it to run the 2.3. It will work, though, and gives you the opportunity to play with things more, potentially opening up a whole other realm of capabilities for that engine.
I forgot to mention the turbo. To my knowlege none of the TC/mustang/XR4Ti turbochargers had any sort of actuators or solenoids on them. Just a boost reference hose/port that goes one to the wastegate and then the other to the boost control solenoid. Remove the BCS and all the tubing. Install a manual boost controller from the site above (stinger). Used to be a popular brand, boostvalve.com, but they've changed theirs up and they are no longer the quality that they used to be-I have one and the difference between 11 psi and 25 psi is about 1/8 of a turn of the adjustment knob; and that's with the knob backed out almost completely. The stinger valve works better. If not intercooled, stick with about 10-12 psi and no more. With a good intercooler you can still run 12 psi boost but you will have a lot more torque available; also you can then turn the boost up to 18 or so without too much issue assuming you have the 35lb injectors, large VAF meter, and the correct computer to run /recognize them. THe stock SVO turbo's were TB0344's (aka T3) and are fine to about 300hp. The t-birds (87-88) had a smaller turbo and are wheezing at 250hp but also they hit harder in the lower RPM band than the T3 does. But none of them have actuators or solenoids other than the BCS which I addressed, so if you have a turbo with actuator or solenoid on the turbo itself, it is not factory. Does it say "Holset" on the turbo? Those are common swaps....but they are generally lazy down low at the gain of a nice top end punch.