This is more a whinge then anything else; it's also long to try and avoid a drip feed situation.
Basically my husband and I are weary of both of our Mother's being condescending know it all's and mistaking us for pushovers.
Here goes...
My husband and I are expecting our first child soon. Our mother's have offered to help us out afterwards, 2 weeks each staying in an airbnb nearby. My Mother lives in another country so is mostly coming to see the baby tbh. MIL offered to come around and help more because I have Bipolar Disorder and we don't know yet how that will play out after giving birth. MIL's partner is bipolar so she has experience with the disorder although not in a postpartum situation.
Okay everything fine so far. 
We are aware that just like baby could be early she could also be late and we want to have the time my husband's on paternity leave to just be us. So we asked for their visits to come a month after due date. To be clear we aren't opposed to visits from family after the baby is born at all, just want our own space on a daily basis after we first bring her home.
Our mother's are both extremely extroverted and wear us out quickly, as we're not like them and our flat is just 1 bedroom so it's not ideal having so many adults here at once with baby. Which are the other reasons for having them here later.
After having firmly and repeatedly told my Mother that she can't stay in our flat due to a lack of space and that we're sure we don't need her to come sooner she finally relented and bought an airline ticket for a month after my due date.
This was a struggle since at one point she told me via IM that she had to come right after the baby is born because "Ya'll don't know a frazzling thing about babies." 
Knowing the condescending tone she would have said that in and with her dialect that annoys the shit out of me when she's being like that, I almost told her not to come at all. She also at one point asked if she could come right after the baby was born and if my husband could take his paternity leave after she left. 😑 You just can't make this shit up.
(Let's not dwell on my Mother's questionable use of the word frazzling.)
But that was finally all settled...then comes the MIL issues tonight.
MIL informs my husband via text that she's booked off the two weeks before my Mother gets here to come help with the baby. We're puzzled by this for several reasons, 1.) she's retired so we're not sure what she means by booked off, and initially mistook that to mean booked a place to stay already, 2.) we had discussed how we didn't want to risk overlapping with my husband's paternity leave being the reason my Mother was coming a month after, and 3.) it came in the form of a declarative sentence, rather than a question.
When my husband told her that wouldn't work she then proceeded to tell him all the stuff about newborns that she assumes we don't know because we clearly wouldn't have done any research ourselves and are just winging this whole thing... Even though that's the opposite of what we do with anything important.
She was clearly just trying to justify why we needed her to be here.
So my husband asks her about coming for two weeks after my Mother has left and she says "That won't help because the baby will be in a routine by then." Really...our guessing 5 to 7 week old baby will be in a routine at that point and life will be a breeze from then on and also I thought she was coming out of concern for me? Guess not. 😒
This would also cause an issue with my Mom for obvious reasons after being told repeatedly she couldn't come earlier. Now if my mental health was on a sharp decline and we asked MIL if she could come earlier my Mother ofc wouldn't be put off by that, but planning this ahead of time would.
My husband is just ignoring his Mother's texts at this point because she kept going on and on about all the things about babies that we supposedly don't know. My MIL was in fact ignorant to a few important and well known things regarding childbirth when she had her first child...but I'm not her...js...
It's like neither of them are capable of understanding (despite us making it clear) that we know this is our first time, all the research in the world only helps so much, we want time to figure it out on our own, we accept we will make mistakes, are okay with that, and will ask for help if needed.