I know what you mean and it does make sense BUT you dont know how some families work. No matter how much they meet each other or keep updated about each other in their dialy lives but if they dont get invited to their brothers’s nand’s son’s wedding they wl create a drama. Argh! It is ANNOYING and i also tell my parents to not care abt these things but you really cant let it be. But again, the guy’s family should always consider that the ceremony is being held at the other familys expense so they should somehow find a way to cut down the number of people they invite. OR they can always offer to co-host like i said earlier.
For Nikkah, Masjid is the best option and it wl leave out any conflict over your place or his place.