A interesting butterfly of this is that we could see Novgorod either stay Pagan or converting to Catholism. If it stay Pagan it will most likely be a victim of German or Scandinavian Crusaders and end up as either Prussia (assimilated by the conquers) or Estland, Latvia and Finland (natives keep their languages but a small western or westernize elite rule over them). If it convert to Catholism it will likely become a integrated part of Norden, maybe staying Slavic maybe becoming Scandinavian or Low German (thanks to the Hanse).
The other interesting Butterfly is Lithuania in OTL before the conversion to Catholism, it were 25% Pagan (includes the Elite) and 75% Othodocs, here the Othodocs is replaced by Muslims, if Lithuania also convert ITTL, they need to find a way to deal with the Muslims, who is just to many to decimate or drive out, likely they will adopt something like Dhimmitude* as way to deal with them, which together with western emigration could mean that they will slowly become in minority, beside that it could mean that either the Polish or Lithuanian language will take over these East Slavic areas.
*at least until they're a small enough minority, so that harsher methods can be taken in use.