Okay, so this is the third time I've tried to enter this.....
i wanted to start out by saying that we never intended Timmy and Denny to be in the same cage, they both have their own cage and the cages sit next to one another. So we have no issues there.

We have owned 4 male budgies over the last 15 years, and Timmy doesn't act like any of them. (For the sake of argument and consistancy here, i am going to refer to Timmy as "she".) She is not as chatty as Denny and doesn't "sing" or make as much noise as Denny. When Denny is by himself in his cage he will chatter to himself or get very noisy. Timmy sits quietlys, preens herself, plays with her toys or eats. She is not very bossy though. When she's had enough of Denny, she will just go be by herself. If Denny persists on bothering her, she may poke at him.
As far as being "nippy", it's hard to say. She won't let us get close to her. I have been able to perch train her, but she is very resistant to finger training. The only time I can get close to her is in the evening when she is downed out. But forget about it during the day. She just flys away. Unfortunately, i am not home during the day so finding time to train her is usually in the evening.
She loves to chew on the kabobs we have hanging in both of their cages. The kabobs are down to small disks. She was chewing on Denny's kabobs earlier and I got a picture -

I read the information Illusive supplied above (BTW-thank you). When I compare her head structure with Denny's, she does not have that rounded crest just above the cere and she doesn't have those pronounced jowl feathers either. She has gone through a molt, but I can't say that it was a major molt. The bars that went down to her cere are gone though, just a few left a little higher up.
She absolutely LOVES veggies. She devours anything we give her. She loves carrots. I just separated them back into their own cages and Denny has been non-stop chattering, Timmy hasn't made a noise, just sits and preens (just like a woman!! LOL) She seems to be very delicate compared to Denny, but that may be the breed.
When we first got Timmy back in early February, her cere was whitish blue with white around the nostrils. Her cere has changed drastically since we got her.
I will take more pictures in a couple of months and maybe it will be more evident.