Commander Bacara's figure exists just to show that there are worse clone figures than the AT-TE Gunner.
Those custom figures look awesome. If I can get my hands on a second Bacara, I'm definitely using it for the parts.
The sniper rifle is, as noted, a G.I. Joe weapon. It came with three versions of the character Tunnel Rat (V1, V2(Night Force), and V3(Sonic Warriors).