I think the odds of us having four goalies in Belleville are incredibly low.
I don't think we bring back Danny Taylor, and we no longer own the rights to Andrew Hammond. I also don't think it is a given that we waste a contract slot on Driedger who hasn't shown enough positive progression.
How I envision our goalie situation playing out next season, is that assuming Condon and Anderson both play well enough to secure their NHL jobs, Hogberg will begin as the starter in Belleville, while Gustavsson will start in the ECHL with a similar plan to Hogberg where he graduates up to the AHL mid season. It's possible we keep Driedger for one more do or die year, and he ends up rotting away backing up Hogberg, and when Gustavsson graduates to the AHL, Driedger eventually is either assigned to the ECHL (assuming he approves it since he is not on his ELC) or stays on as a 3rd AHL goalie or is loaned to a different AHL team.
If Hogberg somehow manages to steal one of the NHL jobs, one of Condon or Anderson will be in the AHL. While Anderson being in the AHL seems unfathomable, I think the team is at the point where they aren't afraid to waive veterans who they perceive as not living up to their end of the deal. We saw Burrows hit waivers earlier this season.