1 & 2, it depends on what sound i want for any particular song or part thereof. i use pick or finger pick at different times in any particular song and position over the sound hole, near the bridge or on the neck . i have even developed a style (unintentionally) where i use a pick and pluck with my fingernail at the same time, it gives a different sound, which i use on the high part of .
3, i got terrible dents where you mentioned on the strat, which has a rosewood neck, also the neck behind the same frets have worn. i'll sell it one day and let the buyer have a discount so he can get it re-fretted.
4, i usually buy strings that are colour coded. if there's one missing or something, i'll send the whole lot back for a refund.
phill