These are my answers based on an infinite-deck analysis of a S17 game. Shown are increases in house edge. Use 0.0050 as the base for the house edge.
0.0036 = player stands on all soft 17's (and never doubles soft 17)
0.0023 = standing on all hard 16's
0.0013 = standing on 15 and above against the dealer's 10
0.0008 = not doubling 11 vs dealer's 10
0.0009 = soft doubling all 13 through 17 (and never 18) vs dealer's 2 through 6
0.0005 = standing on 16 vs dealer's 7
0.0003 = never doubling soft 18
0.0006 = never hitting or doubling soft 18
0.0009 = never surrendering
Would standing on all hard 15's be the same as hard 16's?
Also this is probably going against some assumptions made in the OP, but I have to assume doing something like hitting a hard 14 against a 6 is very bad, but I see it often at the tables. These people aren't playing my really any rules though so just picking out one wrong play doesn't matter when they are probably giving the house an edge of 10%+.