How would you regulate the training---what if you fail the training that's required to be part of a well-regulated militia? If the right to bear arms would be only contingent to being part of a militia, would the failure void your right to bear arms? (serious question)

Why in your interpretation of government subsidized training/ammo is it a requirement?

If the constitution is a document that explains the natural rights of citizens, and is restrictions on the government (which it is)... Then saying A well-regulated militia being necessity to a free state - would imply that government is obligated to train and supply ammo - any requirements for this to be part of your rights would be null considering the next words are "the right of the people to keep and bear arms shall not be infringed."

Note that it says "the right of the people" (as a whole), not the right of "people" (all of them).

The right is not there for everyone. It's only applicable inasmuch as you are part of the militia, and can be restricted if you're not.

Regulating the militia (just like saying what e.g. is due process) is up to the law, and can be arbitrarily restrictive as long as the overall right of the American people to form an armed militia is not infringed. For example, prohibiting hunting would be just fine.