I'm thinking the opposing thoughts may be according to different varieties of the hostas.
Back Up Plan
Do whatever you decide to do, now.
The wedding's not til October, so in late September assess how things are looking. If not to your satisfaction ... go out and get some pots of mums and plant in among the hostas. Perfect backdrop for those fall wedding pics!
I still think with six months to go, you have lots of time to revive them!