I have six cats, and it has taken different amounts of time for each to bond. The two littermates, after a long, long, time of being besties with each other, now are not. The boy is now besties with one of my 'older' cats..so, time does ALOT.

As to the outside thing, I will admit to 'letting' my cats outside into my COMPLETELY fenced back yard, that is COMPLETELY surrounded by other COMPLETELY fenced in yards. So, in the remote chance they escaped my yard, they are still in fenced in areas. I am ALWAYS out there with them, and they are closely supervised, even still. Having said that, I DO NOT think you should let your cats roam, and certainly not ones that are new to you and the area. That is a recipe for heartbreak. (I don't know why my friends were so weenie about posting their views on keeping the kitties inside...maybe it is the 'new, softer' side of them...I, on the other hand, have no problem telling you my thoughts..he he).