Does an RRIF withdrawal count as earned income for calculating my TFSA or FHSA room?

No. A RRIF withdrawal is taxable income - you do have to report it and pay tax on it - but it's not the specific type of "earned income" that generates new registered-plan contribution room, and these are two different concepts that people often conflate. Earned income, for room-generating purposes, generally means employment or self-employment income and certain other specific categories, not any taxable amount you happen to receive.

This distinction matters most for RRSP room, which is generated based on earned income from working, not from investment or pension-style income like RRIF withdrawals. Because a RRIF withdrawal doesn't fall into that earned-income category, taking money out of your RRIF in retirement doesn't create new RRSP room for you to use, even though the withdrawal itself is fully taxable. TFSA and FHSA room work on different mechanics again - TFSA room generally accrues based on age and residency rather than earned income, and FHSA room generally requires having an account open, as covered in a related question - so "earned income" isn't really the relevant concept for those two plans in the first place. Understanding which room-generating rule actually applies to which account avoids assuming a RRIF withdrawal helps you in ways it actually doesn't.