If in doubt and you want to be 100% sure, than it would be worth to confirm with TAC support. Now, as far as mgmt, say if you have (just making this up) cluster on R81.10 jumto 87 and mgmt was on R81.10 jumbo 78, everything would still work fine, jumbo version makes no difference at all, as long as mgmt is at least same OR higher version than the cluster.
Personally, and this is just me, I strongly advise everyone I work with to keep everything on exact same jumbo (if its same version) and if lower, might as well install latest recommended, since every TAC person will tell you that anyway. I sort of understand their position too, as few of them told me that even R&D these days is less likely to help them if customers dont have latest recommended jumbo installed.
Cheers mate.
Andy