Tbh I am v suprised BB is even 4b/folding at that stack size - very sick lol still I wouldn't give him much of a wider range than say AQ+, (AA) KK, (JJ), QQ and I think it just hit the AQ part. Obv he should probably flat AA and besides I defo don't think ever sizes that way - you also get a lot of nits who can't 4b/c JJ in this spot lol thats why i bracketed them.
With 2bb invested I am chucking away 99 all day long. I am actually JJ+, AK cos really I don't think BB is 4b/folding much at all - still very suprised he cold 4bets to almost 1/3rd of his stack then folds - you also have SB who clearly has something.
Also the plan of 4b/calling - I think we can peel IP and play no A no K altho thats only because there 3bets are quite lowish - I like it a lot vs slightly more 3bet happy players.