Am I gettting this right?

Our new rottweiler pup (10 weeks) spends most of her time when she is not in her crate playing with our 18 month old dog. They display typical behaviour as far as I can see, tug of war and they nip and bite each other and Dexter is remarkably patient with her. This has the advantage of very little opportunity for rough play with the humans (3 smallish boys and me) and she is not nipping/chewing at us at all.

So my question is two fold - is this ok to let them get on with it - she is very rough with Dexter but I am assuming this is all part of her natural socialisation?

Secondly, on occasion when she needs to return to her crate and I pick her up she is a bit growly with me (I don't do this when they are right in the middle of rough play) as I guess she wants to carry on the game. My response to this is just to gently shush her and gently stroke her to calm her. Is this the right thing to do (it seems to work) or should I be telling her NO?

Sorry if they seem obvious but whilst I am quite expereinced with dogs I have only ever had 2 adult dogs in the house and want to make sure I get things right.

The way the 2 play is perfectly normal. The older dog will let the younger one know when she is getting out of hand. As for her getting growly when you pick her up, ignore it. What you are doing now is rewarding undesired behavior. You don't want to do it as it will cause the behavior to continue. Just ignore it. She will stop once she realizes it doesn't benefit her to do it. Don't tell her "no" and don't stroke her. Just carry her to the crate normally, put her in it and walk away.

Ok, will do just that.

Hmm, not sure that this is what I thought it was. She seems to do it more often now - so for example, this morning I was up at 3am to let her go toilet; I lifted her out of her crate, put her outside, she peed and I lifted her back in her crate. About 40 minutes later she started whining which I usually ignore but through the night it can mean she needs to toilet. So I lifted her from her crate and put her int he garden and sure enough she pooped. Now when i picked her up she growled and kinda tried to nip me.

She does this quite often now so it is not just when she has been playing with the other dog - am I overreading this or is she showing too much aggression?

Read my post #2 in this thread. It still applies.