No, it actually takes the initial vetting period into account too. That’s the best tool you have. Remember though that it is based on historical data. Storj earnings depend a lot on how customers use the storage, and this is not possible to predict exactly.
With suboptimal setups they do. If your setup is tuned for Storj, they won’t. A lot depends then if you’re willing to spend time to learn how to make storage nodes perform well.
So far the proposal was presented as something that would affect all node operators, whether big or small. So yes, you should take it into account.
A lot of people here moved their nodes across hardware. There are procedures that aim to keep the downtime as short as possible. Few days of downtime was acceptable so far and will not affect your nodes much.