Interesting point. Unless someone has tried its hard to know. Technically the maxi cost carrycot and the older micralite toro carrycot fit using the maxi cost car seat adapters. I tried the maxi cost one on a tandem pushchair I had that came with maxi cosi adapters and it did fit but clearly was not safe. It was massive, in the wrong position, clearly affected stability etc.
Personally, although I am very much an improviser and have used things in unapproved ways before I'm really not sure the carrycot being unattractive would persuade me to go off plan like this. If it was flawed in some functional way perhaps, but the look of it, no.
Car seats - depends how you function day to day IMO, if you have short errands, school runs etc it could be very useful. If not you may hardly ever put the seat on the chassis. I never did, some people use them loads. Maxi cosi ones are fine IMO but some other infant carriers, like the britax one, have a longer lifespan through having a taller back to accommodate a bigger baby. Also there are rear facing lie flat ones now too, such as the casual play sono and the kiddy one I have forgotten the name of. I think you can fit the lie flat be safe one with maxi cosi adapters but do check on that, could be wrong. Otherwise something like the hauck varioguard could see you through from birth to 4 and give you extended rear facing options, you just lose the option to put an infant carrier on the chassis.
Dunno re the wheels. The wheels vs suspension thing meant I never ended up with a versa longer term, I wanted both. If the gt wheels were inflatable it might be different but they aren't.
Crap okay, that was my waffle! In short and purely IMO car seats - choose the best you can find for your car/priorities, maxi cosi fine but newer features exist.
Carrycot - yes it looks rubbish, IS it rubbish functionally? (I don't know but someone here will).
Versa gt - wheels vs suspension. Hmph. Can't help. I love suspension, I love good wheels, having to choose is rubbish.