which to use? sousedi or sousedé
Those two are completely equal. I am originally from Prague and would use sousedi. I am pretty sure people from Morava would use sousedé... So, your pick.
What about "sousedové" -- if you see this question!
got to see it by a mistake.
anyway. Sousedové is not correct. That said I can see a lot of Czechs easily using that and you would definitely be understood and some people would not even realize it is not a correct word.