Hello dtruex.
It sounds like you have a real mess on your hands there.
From what you are saying there are many possible circumstances that could cause the no start.
It is possible that the antitheft circuits are not connected.
If you have the small black chip on your key it has antitheft.
There are 3 very small wires that run up the steering column to the ignition key cylinder. Check those for a broken wire or pulled out of a connector.
If this circuit isn't working it shuts off the fuel injectors on a start up and will give symptoms you are experiencing.
Also if someone tried to hook up a remote car starter they would have had to hook into those wires and may have damaged them.
If you have further questions, ask and I will help you.

KL

You have a short in a wiring harness somewhere but without detailed checking of the whole wiring harness it is really almost impossible to tell where. As I see it you have a couple for choices. 1: Remove everything they added as far as wires from the harnesses and make sure you don't have anything grounding and see if that solves the issue. If it does then you may choose to properly add each item 1 at a time making sure you have them correctly installed. 2: Remove all the added stuff, order and replace the harnesses that were damaged. In most cases you can pick these harnesses up at Junk Yards pretty cheap. The main thing you have to be careful of is to check the harnesses before you install them. Now, having said all of that. If they added these items you mention aftermarket and the vehicle was not originally designed to have them there is a distinct possibility they are causing faulty reads on the computer of the vehicle and causing you problems. That would also explain why they might have tried a different Alternator in the vehicle. Unfortunately, just choosing to install a high capacity alternator in a car that was not equipped to handle that originally is bad in that you can overload the systems and cause damage that is not readily visible. You really don't want to replace a 12 Volt Alternator with a 24 Volt high Capacity to support a second battery or increased electrical need without installing a resistor between that and the computer memory module or other electric computer type equipment as doing so with burn out the modules. I see no easy fix for this. I do highly recommend you remove anything that was not factory installed unless it is something like a radio, and repair all the damaged wires ignoring those added connections then start clean once you get the vehicle started and running good without those items.

Wow thats a mess to sort out.. firstly..

you will need 3 main wires for the alam.. fuel pump,, ignition,, starter.. make sure you secured these wires propperly....

I dont see why on earth they disconncted the alternator.. since you connected it back.. check your battery.. thats why the car died.. cause the battery was dead.,.

the starting and dying can be the cause of a dead alternator ..

I strongly recommed getting a diagnostic done.. if after all that the cars computer doesnt have a fault.. consider your self lucky!!

as for the rest,, no one can talk you through that.. we'll have to see it to fix it.. I recommend getting a pro and have the car rewired..

Get your car scanned at car diagnosis center to get the fault error codes. once the code is there it will indicate the exact faulty part. at www.autozone.com its absolutely free to get codes. also they deal in parts. check out.keep updated. thanks.