Hey guys, sorry if wrong forum for this. Recently started to fix up my MTB, and found some old derailleurs in the shed but don't know anything about them other than they work heh, hoping someone can point out the best ones to use.

These are what I am currently using, rear and front, front one I have no idea of the brand.

These are what I have to choose from, rear and front, the right front derailleur has no screw to seperate the parts so I can't get the chain in unless I take the chain apart (no tool for it), one on the left does. The rear left one I think I got a very long time ago but may have been an expensive one.

Not very good at taking pics. Thanks for any help.