Feeder clubs in inactive leagues?

Possibly a stupid question... but when it comes to choosing a feeder club, particularly a foreign one (for WP's).. is there any noticeable difference in player development if your foreign feeder club is in an inactive league?

Just wondering if I should risk adding a couple leagues in Croatia this next off season (Id heard adding leagues can screw up your save), or not worry about it. (Or go the Belgian route)

The only things I look for in a WP club is as high Reputation as possible and quickest possible citizenship. I'd say it is helpfull for it to be a playable league, but your biggest problem is going to get good young players to accept going out on loan to a poor reputation league/club multiple times.