you've become a mock turning powerhouse, mate
Other than Potter (too late) all your picks are doable, meaning very realistic.
McCellen might not be worth the 26th pick but people will forget about it anyway in a couple years (except those in this draft forum). Versatility in a cap conscious environment is a compelling argument to choose a safe, multifaceted player like Shea but with Brooks/Barwin in fold & Mario gone I probably would address DE/OLB with a longer, fluid edge rusher. So with this in mind, my suggestion for you is Chandler Jones, Syracuse 6053 266. He has more talent, pedigree & fits Wade Phillips profile of what defines the OLB position made famous by DeMarcus Ware.
Quick is getting dinged for his lack of refined skills, he is what he is & Texan fans are more desperate for WR help than probably the FO. Of course it's hard to project trades but I think this is exactly what the Texans will do to address this position with a more developed, game ready counterpart to Andre Johnson. But Quick is a fine selection with the 58th pick.
Green is a flashy player. I'm still not over Dorin Dickerson he flashed in College too but injurys cost him a promising career. Also have flashbacks to Ben Joppru.
Like Center in 4th but in this order, Phillip Blake, Ben Jones, Michael Brewster. You know I would be buying a jersey with the name Brewster on it
Baptiste is projected later. Maybe someone with better length yet impossing size & athletic ability like Akiem Hicks, over three inches taller still 320 range which are plus measureables. He would address this need here rated 4th5th rd.
Like Potter, project him as a LG going forward. Would jump for joy to get him this late.
Bullock is not flashy, but solid & fills need. Would need to get off on the right foot.
Don't know anything about Conrath either. Can he block & play TE?
As Always Good ON You