I agree with the above posts. Crate training is great. Yes, a 3 month old has to go quite often... it's lots of work till they get the idea but it is worth it in the end!!!
Puppies do tend to bark when they play a lot - what does yours bark at?
As for being friendly with strangers - I think that is a good thing - you just have to always keep an eye on her so someone doesn't walk away with her.
