Have developers come close to reaching a consensus on either:
- The definition of micro payments?
- Whether micro-payments ideally belong on the main chain or side chains?
I do not think there is anything to reach consensus on.
According to my research best platform for micropayments should be Digital Cash - Dash cryptocurrency.
They already have many times more onchain scaling and are on road to 2mb blocks in upcoming version.
They are preparing for many features and one of them is turing-complete network governance.
To sumarize this answer, dash is best for it because the high limits for onchain transactions tends to low fees. Other good points are fast confirmation or instant if you want. Very good privacy - sybil proof - while being optional.