""come hither" look or "feminine wiles""
Well those are HIGHLY subjective ideals.
Is it possible for mtf, Yes, and many do, most come close, and some will have a hard time, achieving what I think you mean by "come hither" "feminine wiles" witch are both very poor standards of femininity.
There are MANY variables from, the circle of friends and family, duration of transition, to the age transition started, as well of consistency and quality of hrt and diet.
As for ftm, hrt, time, diet, working out, will usually do it.