1.) Extra contract to play with under the 50 contract limit
2.) Extra cap space on the summer cap (not that I think this is a compelling reason, but I guess you never know)
3.) Less actual money spend (again, this shouldn't matter given the amounts involved but hey, who knows)
4.) May not want to force Sloan to play in the AHL, give him a chance to find a better deal elsewhere (I doubt he gets it but maybe they want to give him the chance)
5.) May not want to force Sloan to play in the AHL and subject the guys down there to a player that may not take a demotion well (don't know if Sloan is that type of guy, I know he wasn't happy about his icetime up here but I don't know how he'd react in Hershey)
6.) May not want to force Sloan to play in the AHL and take up a roster spot and icetime from whatever Dmen they have down there at the time (McNeill, Orlov, Miskovich, Flemming? etc.)
There are plenty of reasons that they might have decided to buy him out. I don't know if any of them are all that compelling other than the 50 contract limit (and that's only if they plan on adding), but with the hit this low they may not have needed a particularly strong reason.
If you don't feel like clicking the link yourself, 34.
33 according to that link. Add the 5 qualified RFAs and it's 38 (I'm betting if Varly bolts, another organizational goalie is signed). You'd assume they'll want to keep a 2-3 contract cushion for possible camp signings and the same for deadline/mid-season deals, so that's 4-6 more. So we're up to 42-44 contracts.
So it would make sense that we likely see 6-8 players brought into the organization this summer. We can expect at least half of those to be of the Fahey/Willsie ilk--Hershey guys that would be strictly injury fill-ins for the Caps.