Some of your prior questions have already been answered but:

1.5 hr callout

RSV lines can be anything but min 10 OFF, though this includes senior line holders who get reserve days forced onto they're schedule. Slow months you may get more, but don't plan on it.

Yes we're all technically on probation all the time.

Bases are provided during class but prepare for frustration. Our class was supposed to get our base assignments week 2 but we didn't actually get them until week 4. We didn't know our sim schedules til one week prior to finishing ground school. Which was a big deal because some people had up too 5 weeks off before sim, others started right away. Lot of stressed and worked up people in my class.