I am an old novice too (58 with about a year in boxing), and I too spend a lot of time seeking the best methods from multiple sources.

Have you thought about the seeming contradiction between #1 and #3 (there really is NOT one) when you are told to "put more weight behind" the punch, and yet "keep you weight back on your rear foot"?

There are multiple ways to get your body (not necessarily your 'weight' but there are ways to do that too) into a punch without throwing yourself forward.

Somewhere in this forum are threads where we discussed this and at least one where I ran down most of the methods to do this....

Dropping, pushing (from feet), turning, pulling back with opposite side, etc....