No question. Give it fuel!

If they are not painted, a good polishing will clean them up. Any pitted spots may still show blemish though

This would be a real chore if you ride much. I would look into installing a drain valve at an accessible location. Fumes will be hard to get rid of unless you air out the tank long enough to let the residue evaporate. Maybe look into a storage unit?

After 8 years, even if pads are not worn, the back plates could be rotting away. Brake fluid flush will be worth while if you have the wheels off for other brake work/ inspection.