Remote Start Module Selection, 1994 Chevrolet Camaro and Other 1980s-2000

I'm trying to select and install a remote start system for a 1994 Camaro, with automatic transmission, non-power windows/locks, electronic trunk release. I'm also trying to select a system that will work with other 80s-mid 2000s vehicles as well, so I can retrofit them as well. The ability to have a remote work with multiple vehicles is an important feature for me. I haven't installed one of these system before and am still trying to understand the particulars of how they work. But I do have a significant amount of electronics experience and feel comfortable doing this work. I've been looking at Avital 5305L and a Fortin Passlock-SL2 V2 bypass device, as it seems to have most of the features I'd like at a price I'm okay with. Desired features for Camaro: - remote start - trunk unlock - mirror/rear window defrost, preferably automatic based on temperature - 4 button controls (lock,unlock,trunk,RS) - remote start for 2nd (possibly carbureted) vehicle - (bonus) 2-way confirmation - (bonus) additional auxiliary channels - would prefer non-LTE and/or cellphone based solutions, although I could be convinced otherwise. Additional future considerations for other vehicles: - multiple cars per remote - multiple remotes per car - diesel wait-to-start - turbo timer mode (preferably with control from external logic input, eg. button or EGR temperature) - pitstop mode (keep vehicle running w/o key) 1. Is there a better solution for my application(s) than the Avital 5305L? 2. I see that the owners manual talks about a Bitwriter 998 being needed to program this unit. Is there another way to program them since the Bitwriter is hard to find? 3. Are there any other devices I need besides the 5305L and Passlock-SL2 V2 for the Camaro?