not the best install but not the worst either. Ideally you should not be able to see or find any of the wiring for the alarm and I prefer solder connections over crimp but it should do for now.
no that is some of the factory wiring that you have circled. Look at pic #2. See the white hrns with all the wires comming out? That single black wire that is not in the hrns is the ant and it shows that it is an older alarm with the old remotes. The easy way to tell new/old is that the older remotes had a red led.
Now as I said I am %95 sure that the sidewinder/viper/python remotes are all interchangable as long as they are in the same series and programming these is really really easy. All you need to do is turn the key on, push the little black button you use to disarm the alarm and then while holding it push button #1 on the remote. I would be really suprised if a local shop would not be willing to at least try in order to sell a remote so I would not bother calling but go in and talk to them. Make sure they are a DEI retailer and just let them know you need the old(red led remote) with two buttons on it.
I have access to a 12v industry forum that the only people allowed in it have to show they work in the industry. I will put a post up there and see how long it takes to dig one up but there should be one there somewhere. It might take me a few days to locate it, and then to get it so until then I would still try your local shops to see if they could help.