I'm just a mapper but I'd jump at the opportunity to remake this game. We just need a heap of resources to do it: alien models (including Preggo Queen and Newborn), gun models, animations, a complete Auriga texture set, and to somehow grab the sounds from the original game. It'd be great to have all those resources available to do it.
I like your base attributes idea. Maybe Ripley8 should be faster and stronger, Call could probably be more durable and take more damage, Christie could have great gun accuracy, and DiStephano could maybe carry more guns than the others or something. That's just off the top of my head, but they could all probably be worked with a bit more.
A remake of this game is exciting to think about!