Is it okay to turn on Excel’s “protect sheet” feature to lock/protect against accidental changes to cells that are marked as “locked cells”? For example, to prevent formulas from being erased or overwritten?
No, I do not recommend doing so. Even if you configure the sheet protection to allow for inserting new rows, if you try to insert a new row in a register, the formulas that are needed won’t auto-populate into the new row.