I think it is better to have two accounts, with the same subscriptions, on two vastly different instances. At least for now.
There are going to be a lot of growing pains with upgrades/updates, and things breaking. As it stands right now, if “lemmy.world” goes down, half the lemmy-verse is inaccessible.
If I have another account on say “lemmy.one”, I can still connect to all the other instances (except for .world of course).
New people are going to gravitate to the largest instance because human nature suggests people want to belong to large groups. That is the intent of your point #1, to spread the load. I would clarify the objective to explain why people shouldn’t have their only account on the largest instance.
Example using US states: I’m on the Pennsylvania instance. I can see what’s going on in the other 49 instances, as well as the Washington DC instance (through federation). I should still have a representative in DC just in case.