First, you guys are doing fine by normal standards. But if you want to do better than that, you guys are putting the consumption cart before the savings horse.
Can you do it in NJ? Dude. You're spending 1/3 of your take-home on fluff -- uncategorized miscellaneous, fancy groceries, eating out, vacations, car leases, you name it. If you saved $2K of that alone, you'd be on track to retire in @25-ish years, even ignoring everything you've already saved and the money you are putting away in your 401(k); take all that into account, and you're probably done in less than 20. If you want to make a change, you every possible opportunity to do so.
What you can't do is FIRE AND buy a house AND have a kid AND owe $200K plus in student loans. This is where the consumption cart comes into play: when you took on those student loans, past you bought an education and committed current-and-future you to pay for it. Even if you and your DW put every penny toward those loans and had zero living expenses, you guys would need to work for two years just to get back to even. Think about that: you guys have indentured yourselves for two solid years, after all living expenses, for the privileges of holding the jobs you have now. And you have barely even begun to tackle those past obligations -- really, unless you are on track for PSLF, IBR is just kicking the can further down the road -- instead preferring to blow that couple of grand extra a month on fun stuff. So after working for however long, you STILL owe two years of your working life to pay off those loans. And now you want to know how you can FIRE by adding on even more debt for even more consumption? Make no mistake about it: a house is a consumption item.
Now, as I said, if you want to retire at 65-70 like most people, you are probably fine. But if you even want FIRE to be a possibility, you can't afford fancier living arrangements until current you (i) has paid past off past you's consumption, and (ii) is socking away sufficient cash for future you's needs.
So how do you do that? First, you figure out how to max out your 401(k). You are in a high-tax state, so every dollar you put aside pre-tax saves you a bunch in taxes. Second, you look at a real payoff schedule on those loans. IBR is just treading water at best; you need to face that reality and start digging your way out. Third, you work on increasing your income. $100K+ for jobs that pay $60-70K/yr is not an awesome return on your investment. Do you have a path up to more promotions/raises? If your DW throws herself into her business, does she have a possible serious upwards trajectory, and can you make more money by supporting her in doing so? What about that side hustle -- can you monetize that more effectively? Every single extra dollar you can bring in will fill in your current hole just a little more, and build up your future 'stache.
Finally, the kid: despite your financial situation, at 30, you really do need to be thinking sooner rather than later. So take @2 years to really whale on the debt and savings -- and use that same time to focus on the realities of your budget and loan payoffs, to talk with your wife about the lifestyle choices that you'll have to make to add a kid or two (daycare/part time/SAHP) and what that does to your budget and FIRE timeline, etc. Figure out how to stay in your current rental with the kid until you have a significantly positive net worth. The idea is to fit your kid into your plan, instead of having a kid and then be in the same spot 10 years later wondering what the hell happened.
I get the sense that you guys are thinking along the standard American track: ok, we're married, we have jobs, now it's time to have a kid; ok, but if we're going to have a kid, we need to own a house -- and it needs to be a bigger one, because of course once we have a kid we'll need more space; etc. But that's not the way life works. You don't get to have a new house just because you're having a kid; you get a new house when you can afford it, and when spending more on cushy digs doesn't get in the way of higher financial priorities.
So, yes, you absolutely can do it. You just need to figure out for yourselves how much you actually want to, and what you're willing to give up to get there.