Whether they are low-high or high-high potentials will make a huge difference. Smith, in particular, could go from adequate to all-conference, depending on that.
Newkirk is OK, not great. It will help a lot if you can (as you mentioned) get him starts/minutes early in his career.
Smith is the best of the bunch, and could be a real coup if some of his key highs are high-high.
Lewis and Hanson both (but especially Hanson) strike me as players without real positions. Lewis is slow for a SF, but zone will at least help mitigate that somewhat so he's not picked on and apart by opponents. Hanson, though, would be brutal at SF (speed) and for a 4-5, where you plan on playing him, that rebounding may be real trouble in the zone.
Overall, not bad for B prestige. A mix of solid, projects, and (potential) stars. Did you send scouting trips to know about high-high potentials?