Purchasing a 2nd property question as a married couple

[Youngwoon Han]

Hi Bigger Pocket community,

Assuming I should consult a tax/mortgage professional, I'd like to ask y'all for knowledge a guidance here. 

About me: I own a 2-unit house that I have been house hacking. I have a conventional 30-year mortgage. After the expense, it had $500 cash flow shown on my tax in 2022 (annual haha). For 2023, I supposed it'd be similar. I did move out of state where this property is located due to a job that my spouse got. I'll have my first property converted into a full rental investment unit in 2024 with both units occupied and a little bigger positive cash flow.

My spouse made an insignificant amount of money in 2022 and she only worked since August 2023 (Appx. $35K), I'd like her to have one more year before we get serious about purchasing a house in the newly relocated city (Columbus, OH) for multiple reasons. This means the soonest we are shopping for mortgages/houses would be sometime in 2025. My spouse does not own a property and if she becomes the only person on her mortgage, it'd be her first mortgage. I have also been thinking about buying a property on the same schedule -- let's say I'm looking for a 2-unit while I live in one. It would be my 2nd mortgage. I assume I should probably go conventional since I am not a first-time home buyer. I believe she will make enough in 2024 for her to get a loan that would allow her to purchase a house within her budget (Her DTI right now is 0%). On the other hand, I project my DTI under 30% with the current rent in Columbus + payment for the first house. Idk if it is relevant, but we probably won't be able to do the full 20% on downpayment.

Questions:

1. Is this realistic/viable?

2. Does this mean we should file taxes married but separately? Would either option make a difference (married filing jointly vs separately)

3. Anything I should be aware of?

Thanks