Right - accomodation: Everyone fills in the forms at roughly the same time, around march/april ish as far as I remember. The difference is that if you're unconditional it gets processed as soon as you send it back. If you're conditional then it wont be done/confirmed until after results day when the Uni knows you're coming here.
Freshers pack: Nothing that much to do with the uni itself, although it does have forms for their records, medical, library/IS card etc and a manual of sorts for the first few weeks; you'll have a LOT of things to do and see. The majority of the pack is stuff from the union like bus pass forms, sports centre membership, freshers week details, offers, etc etc etc. This doesn't go out until after results and you're confirmed as attending.
Hope this helps!