#1 - Gallienus, PAX AVG reverse #2 - I "think" Tetricus II but I'm not 100%. Reverse shows Sacrificial implements #3 - No idea. Lots of different options for LRBs. With no legend on the obverse, I can't tell for sure.
You'd get many more responses if after uploading the images you clicked "full image" so the photos appear in your post rather than as thumbnail attachments. Many people, like me, won't often take the time to click on the attachments.
3 - I think Gratian - GLORIA NOVI SAECVLI Added... here’s some interesting info on this reverse type: http://esty.ancients.info/ricix/type9.html
Those are a bit harder due to a few options when the photos aren’t quiet sharp enough to be sure... first one - Constantius II - Campgate - PROVIDENTIAE CAESS - Trier - This one would be easy enough to find an exact attribution. Someone should be able to help with that. second one - I think this one is Constantine I - GLORIA EXERCITVS - Probably Trier too. The legend looks to read CONSTANTINVS MAX AVG Edited... to remove my initial guess of Constantine II... it can only be Constantine I edit 2: on second look, it seems to maybe read CONS GAMMA in the mint mark, so Constantinople for coin 2
For that above campgate: Constantius II FL IVL CONSTANTIVS NOB C PROVIDEN-TIAE CAESS STR dot-in-crescent Trier RIC VII Trier 480; Sear 17618 326 ad