Some hefty conversions here. The simplest are the two guys with the copy of the 40k rulebook; pretty much just kitbashing with parts from the Dark Angels Veterans, Terminator and Command Squad sprues.
The smoker has a bolter from the Dark Angels Veteran sprue, and is scratch built from the waist down for a lazy, leaning pose. The head is Catachan in origin, and screamed out for a purple tie-dye scheme. The hand holding the cigarette (yeah, right) is from the Sniper Scout sprue, and has had the appropriate fingers spread and a new wrist sculpted.
The marine with damaged armour uses a Catachan arm with a sculpted shoulder. The original marine arm was drilled out and bits of guitar wire were used for cabling. The gun arm is a simple cut and glue repose.
The missile launcher marine is almost completely rebuilt. Rather than sculpt the legs entirely from scratch, they were cut at the hips and knee. The kneepads and feet were removed. The head is Catachan, with the headband and hair removed and replaced with a greenstuff scalp and guitar wire cable. The canteen, strap, knife sheath, feet and kneepads are also greenstuff. A little water effects was stretched between the mouth and canteen, and down the chest to represent water. Or booze. Probably booze. Bases are resin, by Secret Weapon Miniatures.