Pocket hole jig needed?

I need to replace the legs on an outdoor table and benches, the legs of which form an "X". Original redwood abt 20 years old and painted many times over the years.
Questions-
1) Do I need a pocket hole jig to attach the tops of the new legs to the underside of the table / benches? or just cut out a "V" notch with a 1/4 inch chisel and drill up through this?

2) Guess the setting will go to heaven one day (or to elder son), is it worth getting the new timber in redwood or would treated pine be ok? - taken that it will be painted so original colour not a problem.