withdrawal of excess contribution:
before tax due date including extensions: positive earnings allocable to the excess are taxable on the Line 4b for the year of the contribution. negative earnings are ignored; therefore, do report the entire requested amount as returned .
positive earnings removed are penalized 10% if you are under age 59 1/2.
after tax due date including extensions: you distribute the excess amount being carried forward on 5329,
(or offset it with currently allowed contribution) .
earnings stay in the Roth account.
This should answer all your questions.
It's not as complicated as you seem to be making it.
@gjgogol
