There are 6 U's.

Nobod- can -ull- understand the -eaning o- lo-e unless he's o-ned a dog. A dog can sho- -ou -ore honest a--ecti-n -ith a -lic- o- his tail than a -an can gather through a li-eti-e o- handsha-es.

Rottie(I,R,O,L,B): 58
Fuzzy317(S,C,G,N,U): 47
Karen(E,T): 38
Logan(A,D): 36
*LabLoverKEB*(H): 12

Letters left: F,J,K,M,P,Q,V,W,X,Y,Z