Hi pokitoki
HB is not being phased out, at least not yet.
As you are not in receipt of HB, if you move to some where you need to apply for help with housing costs then you will have to apply for UC and claim housing element, as it will be a natural migration you will not be eligible to claim Transitional Protection.
As you are in the support group you should be eligible to get the LCWRA element when you apply for UC providing you ESA claim is still live when you claim. You will at some stage be sent a review for WCA.
Speak to your local Welfare Rights Organisation;
advicelocal.uk they will be able to explain everything to you.
Gary