Don’t make it so complicated or overthink it. Just go! I mean if you’re not bound by work or school or pregnancy, and it seems like you want to–just GO.
Your husband thinks it’s no big deal, because he probably has stronger ties to the place and/or realizes that no who knows what will be in a years time. No matter where you go, there’s always a risk of safety and getting sick, so take precautions and leave it to Allah.
The whole “if bhabi doesn’t go = you don’t go”…it’s probably because if she’s the only other bahu, everyone else is an immediate family member going, not an outsider. I know it seems weird, and bla bla but…ok i don’t know. Ask him why he thinks that?
If you have a normal, and not toxic/abusive relationship with in laws, then it is better to go with a group than go alone. And if you do get pregnant around that time, then just deal with it then.