Those HS55s are pretty wimpy. For p-p setup you'll need something stronger and also a servo that centers more accurately. And, you probably want a servo with a bigger screw for the servo arm since you'll be wrapping your string around it. Of course, you can use the 55s and they will probably be fine, but a bit marginal. Nothing says you need to do a p-p set up, the supplied pushrods will work fine but will probably add 1/3 ounce to the finished weight by the time you get done balancing the tail weight with nose weight. OTHO, a better servo will be heavier too. So pretty much the same.
For hinging the flaperon on the bottom you will want the hinge tape on the bottom of the wing. The bevel, which gives the flaperon room to move in the opposite direct, would go on the top. Doing this will allow you to get more movement downward and increase the amount of flaps you have available. I think the AH directions tell you to hinge the flaperons on the top of the wing (IMHO, you should do the opposite).
Stripes are good but remember that by the time you put enough paint on the wing so it looks great it'll be too heavy. Think light coats. Remember that you are trying to save grams so you can eventually save an ounce. Stripes are optimistic, they tell the world that you fly so high you need help to see the plane!