Spats and Dug beat me to answering, but here's confirmation for anybody who needs it. Dug is right that the "percussion caps" are the copper jackets from modern bullets, which got stripped off by hard impact. The two large-caliber bullets with three WIDELY SEPARATED body-grooves appear to be modern repro Lyman Mold Minie-bullets, made for Blackpowder Rifle shooters. In addition to having the widely separated body grooves, they can be distinguished from civil war original ones by having a very wide, thin-walled, extra deep base cavity. A well-focused closeup of those two bullets' base-cavity would to definitely identify them.
Although it SEEMS like there's no civil war era relics in your finds so far, please do not be discouraged. Keep hunting... preferably in an area which has some documentation of civil war military activity in that area.