(i) has not attained the age of 19 as of the close of the calendar year in which the taxable year of the taxpayer begins, or(ii) is a student who has not attained the age of 24 as of the close of such calendar year.Here, in black and white, the law specifies that the determination is made as of December 31st and applies to the entire year.

Contributing to a Solo 401(k) or SEP-IRA can reduce taxable income, and Section 179 or bonus depreciation lets you deduct equipment costs upfront.

If I choose the rental, then all income generated will be taxable income moving forward, because none will be off-set by the interest I could deduct.  

If you do so - 100% of the cash converted is taxable.

When the 1031 is complete the exchanger will refinance the new property and use the cash from the refinance (now non taxable) to invest in syndications.

@David Sam Cost segregation can benefit a property under $400K by accelerating depreciation to offset taxable income, especially if you qualify as a real estate professional or use the short-term rental loophole.

By accelerating your depreciation schedules, you reduce your taxable income which in turn increases your operating cash flow.

In theory you could get a hold put on your taxable valuation at 250k for a few more years.

You have your selling price, minus all selling costs, minus your purchase price, that’s your taxable gain.

Any excess proceeds not applied to the investment portion may be taxable as "boot."