Predictions:
Rex is struggling with coming out of the closet, big-time. He’s been avoiding sex for months; his wife has made it known that she’s willing to go with him into whatever kink he wants, and his reaction was to tell her she sounded like a whore; and he cries when he ejaculates. Plus, I read a spoiler somewhere that one of the men on the show turns out to be gay. I don’t think it’s Mary Alice’s husband, Lynette’s super-fertile husband, Carlos, or Mike. Ergo, Rex.
The note to Mary Alice will have come from that Gladys Kravitz character about something innocuous – I’m thinking that they were watering their lawn during drought restrictions or something, since Bree commented on the husband keeping the lawn so nice in an earlier ep. Mary Alice jumped to conclusions that the note writer was referring to her really big secret, and committed suicide.
The suicide of his mother caused Zach’s suppression of his memories of Dana to fail. I think, given his hair trigger temper and the fact that his father flatly forbid any psychotherapy, that toddler Zach accidentally on purpose killed baby sibling Dana in one of those tragic jealousy things. The family packed up the baby corpse and moved out of town and changed their names.
I think the Mike Delfino investigation thing is going to be the real surprise. I’m thinking Carlos is involved in some shady business stuff, and we’ll see Gabrielle lose her privileged lifestyle. Of course, that begs the question of how she’d stay on Wisteria Lane. Maybe she’ll move in with one of the others?