Hi Anna
You have a lot on your plate. Unfortunately, some of your questions are outside the remit of this forum, and you need to speak to a specialist welfare advisor who can look at your case, especially when you will be claiming as a single person and in a new area of the country. If there's time, I would try and get help before you go.
advicelocal.uk/ Hopefully, you will be able to use the link and find someone where you are currently living.
Nothing will harm your case by ringing the DWP to try and find out where they are with your review. Lots of people ring and ask. In the past, we might have been able to give you a timescale, but that's not the case anymore, as we have some members waiting more than 18 months to hear about their review.
BIS