Speakers, floor standing or Bookshelfs

1:No..
2:Stand mounted,yes & better imaging.
3:Full range & subs,probably be easier to match everything up setting them up as small...JMO,YMMV..

I personally prefer to have high quality full range speakers… without subs. Although I have had floor standards with two subs for about thirty years.

Good quality floor standers are designed for coherent sound across the spectrum.

Then there is a question of what you want. Are you going for coherent realistic sound or highly accentuated bass to slap you I the chest. It is very typical when I go to a high end audio guys house he has the subwoofers way too high… way toooo high! This will muddy up the imaging and cover up other frequencies. But you spent a lot of money you want to hear them… But it is all a question of what you are going for.

I am after musical and natural… not a cartoon or a heartless revealing system sticking details in your face. I love great imaging, and have it. But you can get great imaging cheaper (big generalization) with small stand mounted speakers with subs. But, typically there are trade offs.

sounds like you have a pair a subs and 2 floorstanders? My 2 cents: be in a small room, you would be better off with bookshelf speakers. With many ifs and buts as there are so many variables.

More flexibility and (usually) better bass with (at least two high quality) subs.

Stand mount main speakers can image better but the output capability must be sufficient for the size of the room you are trying to fill. Puny stand mounts with subs doesn’t work for me. I would look for main speakers that legitimately cover down to 50 Hz, or a bit lower, so the subs are only covering the bass. It is better if the stand mounts are designed to operate optimally within their given frequency range and do not attempt to cover the lowest octave using their small’ish drivers, which can muck up the bass and the midrange.

As @ghdprentice pointed out, it is also very important to roll the subs in carefully and not run them too high or too loud, as a little less is often just right.