And there will be a time delay of a day or so before they post, then a couple of days to come over from LeClub to IB+.

Unless you have any other hotel scheme or credit card points (Amex MR, etc) that can be transferred into IB+ directly, then your options for speed will have to be along the lines of buying them one way or another.

Either buy in IB+, or buying them in a hotel scheme, etc, and transferring them over.

N.B. I've not personally bought Avios in an IB+ account to activate it, it should work (I think, fussy memory, I've seen it done it in a family members BAEC account).