The shotgun on there is not a SPAS-12. It looks more like a modified Mossberg 500 or Remington 870. Pretty much your typical sawed-off shotgun. The SPAS is more of a military weapon.
EDIT: And that sniper rifle looks like a PSG1, but it's hard to tell for sure.
SPAS-12 (for comparison):
EDIT2: I think ZIM is right about the MP5. At first I thought the "SMG" was an MP5k, but I've never seen an MP5k without the grip on the front.
The first is a SPAS-12, the second is likely a Mossberg as mentioned above, and the third is... well something else. Probably not a Mossberg or Remington since companies make pistol grip mods for those guns. But it could be anything, really. It looks kinda like my Savage M30J, which has a shortened barrel and cut off stock (to form a pistol grip.)