First, getting a house loan to "save money with the Mortgage Interest Tax Deduction" does not work. Ever.
No loan = 0 dollars to the bank in interest.
$1000 income that might have gone to interest is now taxed at, say, 30%, so you pay the Feds $300.
Loan with $1000 mortgage interest = $1000 to the bank in interest.
$1000 income devoted to interest payments means you don't pay the Feds $300.
You are losing $700 a month by "saving money" this way.
The banks like it, though. Personally, I would rather contribute the $300 to reduce the national deficit rather than to a banker.
Here's the only way to make money with that deduction that I can think of. You to decide to buy a house for $100,000 in cash.
The buyer says, no, he'll only sell it to you for $1 plus $99,999 in interest. Note that $1 + $99,999 = the same $100,000 in cash you wanted to pay anyway. You take the tax credit on the $99,999 interest, reducing your fed tax liability by a fair bit.
I suspect you would also save money on room and board once you're in prison on some charge or another, but I could be wrong on this last point.
Second, your spouse doesn't need to quit their job to "start a family" until she's pregnant and due to deliver.
Third, that newborn infant will be confined to a crib or your arms for quite some time. They don't need a big house with a big yard. They can't use it at that point. Nor will they care.
Fourth, as long as there's a park nearby that's not chock full of derelicts or otherwise unsafe, you don't need that big yard for several years.
Fifth, if you're like most American parents nowadays, you won't let the kid play in that big yard by themselves anyway because it might be "unsafe". (At least not until they are old enough to run away and make lots of noise while doing so.)
In other words, all the reasons you've given for buying a house you can't afford in order to start a family have no supporting basis in objective reality.
Get a cheap apartment and pump that money into paying off those student loans. If you keep your living expenses really cheap for the next 2 to 4 years (and pump your income up to the $100 to 120k range), you can have those student loans off your back forever. So, even if you had the kid a year from now, just after moving out of your relatives' home, you could easily afford a house when your kid is 3 to 4 years old. If you kept your same inexpensive lifestyle for 2 more years, you could have a paid for house by the time your kid is 7 years old.
They you would have the money freed up to do loads of fun things with your kid, who would be of an age to start appreciating it.