Clark won't be staying I wouldn't have thought, I don't recall him even making a matchday squad and while he'd make decent cover, Fleming would be coming back from injury so I don't know if he's even needed.
Flores I think will go, Mayer might stick around as cover, Scott will probably go out on loan, Eaves will be kept, the youngsters will go out. I'd be surprised if we weren't working towards something for Whyte and Slater because that's two signings that know the club and can slot straight in.
If you look at the starting XI, you could play the side that started against Wigan and it would be pretty competitive. Not title winning, but it'll give anybody in the division a game. I'm not saying that we don't need signings, but 8-10 is a lot when you think about cost, players staying etc.
For me, a striker should be the priority, as Magennis has injury worries and we know Eaves isn't a ready made replacement at Championship level. Niasse is available on a free, he'd do a job for us. Signing Whyte adds depth to the wings, while Slater adds to the midfield trio. A bit more cover at centre half would be useful, I'd look at getting Sonny Bradley back from Luton, which would increase the home grown quota too.
I haven't see if we have sorted Alfie Jones out a new contract, presumably that's also a priority now that the season is over.