This Q/A is super helpful in handling excess contributions that weren't withdrawn past the deadline. To summarize,
- Follow the instructions in the thread to mark the contributions as income for the impacted year
- It's ok to wait to actually withdraw and incur taxes until retirement
I have a couple of specific questions on this though;
1. Does it matter if this was a mix of pre-tax and post-tax contributions? e.g., should I not include the after tax contributions since they've already been taxed for the year?
2. For return of excess, the amount to withdraw is +/- the gain/loss on the contribution. Should I enter that amount as additional income on my tax form, or just the base overcontribution?