1) TL;DL doubles/triples are because splits = better hit rate, and then power = higher outfield hit rate, and then 2B/3B rate = speed + BR + manager aggressiveness. Batter's ratings are weighted approx 60% on doubles and approx 85% on triples relative to pitcher's ratings.
Splits are simply hit frequency, and then there's secondary RNG calculation of home-run-per-hit. Then on non-HR hits, there is tertiary RNG of doubles-per-hit and/or triples-per-hit. Doubles volume is influenced by total volume of hits but doubles
rate (and triples rate) is some combination of power + speed + baserunning + fielder ratings + BR-aggressiveness manager setting all sewn together. Push/pull determines direction L/C/R (which matters), and Power determines frequency of pure singles ("thru the hole") vs outfield hits ("line drives" etc) and then your better baserunners are more likely to reach 2nd base on an outfield hit than slower/dumber runners
3) ehh there's some residual batting average that guys gain via contact but it's very, very low. Contact matters to any hitter with elite speed (90+), and also when you're playing against teams with poor defense. Fast guys tend to dramatically overperform relative to what their splits predict. Vs poor defense you get bonus singles on minus plays and bonus runners on errors. Also you get bonus baserunning advancement on productive outs. But aggregately its value is a tiny fraction of the other ratings.
Additionally,
[Contact is] not just the reverse of pitcher velocity, which I think is valueless.
In fact, the opposite is true. Strikeouts are extremely valuable for pitchers whereas a strikeout is essentially meaningless for hitters relative to other types of outs. It's a known paradox of real baseball. Velocity is good, contact is valueless
7/16/2018 3:49 PM (edited)