Proggies have a remarkable ability to change what's high and low status almost at will. See: gay marriage. Indeed, this would be a useful technique to steal from them. However, I want to get properly on the record predicting certain hard constraints.
Can't be acceptable. (Not ephebophilia, that's historically and archaeologically normal.) The revulsion is hard-coded and is reinforced by the obvious selfish threat to their own children.
Total public nudity.
Wifmen will always have a body part which the showing thereof means 'have sex with me,' and they will for some bizarre reason insist on covering it. (Caveat: hardcore exhibitionists.) While I'm skeptical, I hear in some cultures it's the belly button rather than the other couple obvious choices.
Tolerance of different behaviour.
Different appearances are apparently easily tolerated. Used to be clothes counted as behavior, but they don't anymore. See also: dyeing, tattoos. While clothes still mark class and phyle leanings, most will tolerate odd dress as long as they strictly behave according to the code. At no point will odd but harmless be genuinely tolerated - being odd will always count, in and of itself, as being harmful.
Suggestions for this list are appreciated, though note I'll be skeptical to a comical degree.