Speakers for Room Size

@prof agreed that big speakers can work in smaller rooms - there may be limitations to their ultimate performance but even then they can sound better than smaller speakers.  The issue as you point out is that you can't really say for sure until you put those speakers in that room.  To the extent that a set of speakers has the ability to tweak output (whether through jumpers, resistors, etc.) that certainly minimizes the risk of not having a speaker work well in a room that is smaller than typical for that speaker. 

Should work, I see no issues, go for it!
IMO: should produce a fuller richer sound.
I have placed large speakers in rooms the size you describe with great results. 

When my audio system was in my living room (13x24), I had a pair of standmounts with sub woofer.  The larger floor standing models I was considering had a law WAF (wife acceptance factor), in that smallish living room.
When I moved down to a 24x26 "man cave", I did upgrade to a pair of floor standing units (with a pair of sub woofers).
One thing to think about (if you go with stand mounted speakers and a sub woofer or two), integrating sub woofers can be really problematic in some rooms.  Certainly that would not be as much of a factor with full range floor standing speakers.