OP has not been NOT nice to them. She's asked advice about if she's being unreasonable - ie, she doesn't know if she is or not and she's asking feedback.
Some of the replies have been OTT but the general consensus is that she isn't being unreasonable and she sounds pretty sensible, I'm sure she's not going to go in all guns blazing.
Fwiw those sorts of "I hope you get horrible DILs' posts make me more glad I've got my lovely MIL, who would never speak vindictively and nastily about anyone, rather than someone who who wishes unhappiness on someone else like that. Boy 
There is much more deeper controlling behaviour going on with her, I could write several PAGES of an AIBU on her and her treatment of her dc's
BIL is 37 and they still treat him like a child. His wife is not impressed at all
OP it sounds like you are fighting a battle to draw lines here between reasonable and unreasonable behaviour.
If your PILs did not have a pattern of controlling behaviour, you would still be reasonable in getting a bit narked over this, though a tactful word would probably have been enough.
Since they do have a pattern of controlling behaviour, YADNBU. Clearly speaking to them won't be enough so honestly I think all you can do is put much higher fences up or tell them in no uncertain terms and then distance yourselves from them. Is this your first child btw? Your MIL could get quite a lot worse when her grandchild comes along.