Yes, sorry, forgot (I'm shattered). I actually originally forgot to mention that you need to claim DLA (or be one of the few small number of exempt groups) in order to claim for Housing Benefit. However, I realised I edited the post within seconds. I clearly didn't notice I did the same with ESA
So just to clarify, you may be able to claim ESA and Housing Benefit as a full time student if you are claiming DLA. However, any maintenance loan (and maintenance grant) you receive, as well as some other kinds of student finance, will be taken into consideration when calculating entitlement.
And yes, the Special Support grant can be claimed in place of the Maintenace Grant. The difference between the Maintenance Grant and Special Support Grant is that the SSG is not considered as income when deciding entitlement to benefits whereas the Maintenance Loan
When I say that "all student finance will be considered when deciding on eligibility for benefits" I mean all student finance that is normally classed as income (ie. "normal" finance and not the Special Support Grant or Disabled Students Allowance).
I thought this had already been explained to the OP in a previous thread but, after doing a quick search, cannot find the post in which I explained it.