Most people seem to be focusing on the cleaning service or prescription drugs, but if those are non-negotiable, I would try to shave another few hundred off of your expenses from other stuff (groceries, cash, clothes, etc), and adding that to your $1400 "leftover" money, I would try to kill the $16k student loan or $18k mortgage shortage (or both!) to free up the extra ~$300 (each) you're spending on those. If you're aggressive enough, you may be able to pay off one of them in less than a year, maybe both in 1.5 yrs. I echo what a previous poster said about paying down your mortgage and refinancing so you cut out that PMI before 2017. Even if you get rid of one of these payments before the baby arrives, it'll probably put you in a much better spot stress-wise.
As a fellow fed with a staggering amount of studen loans myself, I've been trying to put every cent into my student loan...it's hard especially since like you, I'm pretty new to this, and my husband is still a student (working toward going into academia...and not super mustachian although he kind of has to be now because he's a student...I guess we're actually very similar!) but I will be so happy to see those monthly payments gone and I can add that to savings!
I do applaud you for maxing out your tsp and already owning your home (those are two things I haven't been able to do yet)! However, you mentioned your husband hates his job and you'd love to have him be a SAHD once the baby comes - have you considered the following?
My calculations might be off, but if you aggressively pay off your student loan ($330), get rid of your PMI ($311), get rid of your cleaning lady since if your hubby's home he can do the cleaning ($260), shave a bit more off your monthly expenses here and there (including your husband's commuting costs), that is a potential savings of over $1000/month so your monthly expenses would fall below $4300. If you do this and maybe cut your tsp contributions to less than the maximum, it may be possible for your husband to quit and stay home. You wouldn't even need to worry about daycare since he'd be home. I say this because I make a similar amount as you, and am putting 7% into my TSP and I take home about $4600/month (I'm also paying back a TSP loan). Obviously you wouldn't have a huge cushion in this situation, but your husband would be happier, your baby would be happy, and you'd probably be happier knowing your baby's in good hands and your house will be clean :) Also, whatever promotions you get after that could be funneled straight to your TSP to increase the retirement funds.