a. It sounds like you gifted the property several years ago. The deed is probably enforceable, even if it wasn't filed with the county. Filing makes deeds public, which is useful for various purposes, but I don't believe filing is required to make the deed enforceable. See an attorney if you are unsure.
b. If you made the gift several years ago, you need to file a form 709 for that year. The form is signed and filed separately, is not attached to your regular tax return, can't be e-filed, and can't be prepared by Turbotax. The value of the gift is your share of the property's fair market value on the day you signed the deed, not the current value. Here is the link for past year forms. https://www.irs.gov/forms-pubs/prior-year
c. The fair market value is what a willing buyer will pay a willing seller in an open sale given current market conditions and the condition of the property. The tax value on county records is rarely an accurate measure of FMV, and an appraisal is only an accurate measure of FMV if the appraisal is performed at the time the value needs to be determined. If the property is in poor condition, a fair and accurate current appraisal should reflect that.
d. I think you already made the gift years ago. Filing form 709 does not make, confer, or validate the gift. It simply reports the value of the gift to the IRS. If the gift was made in the past, it was made in the past.
1. Your gift was your portion (1/2 or something else) of the equity in the property at the time the gift was made. If there was no mortgage outstanding, then your gift was 1/2 the FMV. If there was a mortgage, then your equity was less than the FMV and you gave half your equity, not half the total value.
2. To establish the FMV on the date of the gift, you can ask a real estate professional for a retroactive valuation based on historical records. There is no particular requirement for number of appraisals, just that the person doing the valuation must be competent to perform such valuations.
3. Form 709 has the same deadlines as a regular tax return, April 15 (or April 18) of the year after the year in which the gift was made. However, it is filed separately and is not attached to or included in your regular tax return.
But as said, I think you made the gift years ago.
