Your main home is where you live most of the time. You can't change that by declaring it to be so, it must be where you actually live.
You can deduct mortgage interest on your main home and one second home that you own. The interest must be secured by the home, and must be used to buy, build or substantially remodel the home. That means that, if you take an equity loan or mortgage on your main home to help your daughter buy a different home, none of the mortgage interest is deductible.
If you owned or co-owned the second home in MO, and there was a mortgage on that home (to buy, build, or remodel it), that interest would be deductible if you paid it, as your second home. If your daughter paid the interest (and it would be her main home, of course), it would be deductible by her, as long as she was either a legal co-owner (on the deed) or an equitable owner (which I can explain later if needed). But only if the loan is secured by that home--not if the loan is secured by a different property.
Property taxes can be deducted by the person who pays them if that person is a legal owner or co-owner (on the deed). You don't have to live in the home or consider it a second home to deduct property taxes. However, you can't be an equitable owner, only a legal owner. And there is currently a cap on deducting state and local taxes (including property taxes). Unless the cap is lifted, you might not get any actual deduction, depending on the amount of income and property tax you pay already.
If you owned the home in MO, paid all the expenses, and rented it to your daughter, you might be able to treat that as a rental and deduct some or all of the expenses. However, this is a bit complicated and I would want you to get professional tax advice. One key factor is that, to take the full benefit of any tax position, you have to rent the home at full fair market value (what your daughter would pay to rent a similar home in the same neighborhood, or what you would charge a stranger for rent). If you give your daughter a lower-than-market rental price, you lose most of the tax advantages.
