Mortgage interest, dependents and investing in real estate (depending) will help, absolutely, but won’t be the same as for example, doing the max amount ($20k) in traditional 401k. Filling jointly will also be better for both of you, since the deduction will be higher. With the mortgage interest, dependents it will lower your standard deduction and you will have a higher refund, depending on how you manage your W2. Filing jointly has more benefits than disadvantages.

Whats the question? The only way to lower your taxable income is trough traditional 401k, IRA, HSA or FSA and a couple other benefits that are pre-tax. Since you said you aren’t interested in retirement investing, I don’t see how you are going to be able to lower your taxable income by much.