We sign Leeds and Newcastle including the Hertford diversion on passing out. Pretty sure the Bradford's, Skipton's and Harrogate's are covered by Leeds and the Hull's go to the Doncaster men/women. As for traction I sign 90s, 91s and HSTs but not sure what's happening with those seeing as Class 800 (I don't call them Azuma's) certification has accelerated in recent weeks. I hear some are being stocked with food ready for imminent service.
Later you'll be given the opportunity to learn the Cambridge and Lincoln diversions and then there's progression from the main link to the TBird link (67s and 08 pilot) but who knows what's happening with 67s in the medium to long term. Typical day is Leeds and back or Newcastle and back, but a few turns have a trip to the depot at the start or finish. For some it's samey samey, but personally I like it and it's a vast improvement on my previous depot.
Regarding the crew changeover, typically at Leeds you would get an hour and work the second service back from your arrival (so if you arrive at 0945 you'd find yourself working the 1045 from Leeds-London, not the 0915) and it's not too dissimilar for Newcastle unless you're running late. I've pulled into Newcastle 100 minutes late and my southbound working was sat on the platform waiting for me to take it forward. Hope that answers your questions.