It seems that you do not qualify as a first-time homebuyer because you will have had an ownership interest in a principal residence during the two years immediately prior the the buyout.
QDROs do not apply to IRAs. The settlement agreement would instead call for a transfer incident to divorce of a portion of the IRA, which is neither a distribution nor a rollover. However, determining an equitable division of the IRA in exchange for you keeping all of the house would be complicated by the fact that the IRA is deferred income such that your ex-spouse would owe taxes and possible early-distribution penalty on a distribution from the IRA. If assets were generally being split equally, the transfer incident to divorce would be 50% of the IRA and no part of that would be in exchange for the ex-spouse's half of the house.
