I am sure that different IPs have different views and I can only go by my recollection of posts on this subject in the past. The grants are usually considered income, but then offset in your allowable expenses against the purpose for which the grants were given (books and study materials don't come cheap !).
Student Loans are usually allowed to be taken (as you know, the usual terms are that credit over £500 is not allowed without prior approval) as they are not deemed repayable until, often, long after the IVA is due to be finished. Again they will be deemed to be spent on allowable expenses.
I would suggest a chat with your IVA provider sooner, rather than later. Get any agreements in writing, if possible, just in case the wind changes direction later.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk