Judging by what happened last year - most decent courses were not taking anyone who didn't meet the offer. I know of several people who got the right grades but in different subjects (eg. A*AAA but with the A* not on the required subject) who were rejected.
If they have a significant number who miss the offer then it is possible they might take someone who has an A* in the most relevent subject & a B in the least relevent but most courses were over offering in the expectation that some students wouldn't 'make it'.
Edinburgh, for example, made it very clear that the AAA offer was 'non-negotiable'
There is at least one course at a particular University that makes a standard offer but then interviews & decides from the interview what action to take if come the summer the standard offer grades are not met.
I doubt you will get anything firm from admissions officers at this stage as they probably wont know for sure until they see the results of all those they have offered to in the summer but you might get a definitive 'offer or nothing' response if they intend to use clearing if necessary.
My advice (for what its worth!) - in such a competitive situation I wouldn't depend on getting in on anything less than the exact offer & if therefore you have the option, don't hold a back-up offer that you aren't pretty sure of meeting. Obviously don't accept an offer from somewhere you really wouldn't be happy going but with the fees increase it isn't the best year to end up taking a 'forced' gap year & reapplying!
On a practical note - on results day you can log in to UCAS & usually before you get the actual exam results you can see whether your first offer has gone 'unconditional' ie. you have been accepted.
Sorry this is rather a long reply - hope some of it helps.
There are plenty of people about with lots of experience who will be happy to help where they can. Just about all of us have benefitted fron this forum in some way & know what its like to go through some stage of the 'system' for the first time so never worrry about asking what might seem 'silly' questions!
I used to say to the children - never be afraid of asking a question as there will always be at least one other person who wants to ask the same thing but isn't brave enough