the 3 spoilers seemingly have the same picture effects in comparison to when sam emphasized his story flash back of being a pervert child, during sophia and sam event. it could be a dream?
she did go to sleep from last play through believing she went through remorse of what she did with dylan in the swimming pool. the spoilers wouldn't excuse the idea of it being a wet dream during her rem sleep at night and we from the outside are watching the dream state of how increasingly sexual she's becoming.
why could it be sam instead of the mailman?
you could go to sleep with remorse of your actions but your brain will still use any opportunity it could get to feel what it wants to feel even during sleep. after persistent occurrence of sexual moments the brain could find that be top priority of not wanting to feel a certain way, enough to override negative emotions.
the mailman route is exciting and at the same time theres not enough of play through time between these two characters for the mailman to be part of recent memories. on the other hand, sam is which is probably why she sees him instead of mailman. she did accept him as her boyfriend and they did go through their first relationship sexual experience regardless of what happened between dylan and sophia during the beginning of the night after the fact. she currently sees sam as her love partner.
im assuming that when the actual day begins and she sees the mailman outside (probably peeking first out the window (most likely nervous whether it could be sam)) the wet dream could become reality to lead down the filthy route of whether she wants to take off her bra under her sheer gown. that could intensify sexual feelings for the rest of the update with ellie.