Is that a valid combo i.e. my bomb or mine is dropped and dose no damage. Can I re use it like a missile?

Bombs are not secondary weapons, and Munitions Failsafe only works on secondary weapons. Bombs also don't make attacks, so it's impossible for them to either hit or miss.

Secondary weapons have an "Attack:" header in their text.

So this brings up a question, does this mean that the original damage deck's 'discard one of your secondary weapon cards' crit doesn't effect bombs?

So this brings up a question, does this mean that the original damage deck's 'discard one of your secondary weapon cards' crit doesn't effect bombs?

That was my next question

So this brings up a question, does this mean that the original damage deck's 'discard one of your secondary weapon cards' crit doesn't effect bombs?

Correct, as Bombs are not secondary weapons, the 'Discard Secondary Weapons' element of the old 'Munitions Failure' critical does not affect them.

Similarly, Munitions Failure cannot result in you discarding Extra Munitions, Bomb Loadout, Chardaan Refit, or Feedback Array. And it can result in you discarding Hot Shot Blaster.

If it could be used would that mean that if I dropped a Proximity Mine and it doesn't blow up on anything that I could use it again?

Just pointing out how the failsafe does not interact with any current bombs.