[mark sr]

I think I'd wash it with TSP and rinse well [either pressure washer or garden hose] and then apply a quality waterborne stain. As long as the existing finish is weathered and clean there shouldn't be any issues apply stain directly over it.

 

[mark sr]

I stand by washing and using a waterborne stain. I might would mix in bleach with the TSP as the cleaning solution.

 

[mark sr]

#1 probably stays busy and has no incentive to work cheaper
Contractor pricing is fairly constant and is usually the same or lower than sale prices.
Before hiring any painter - check his references!