TREC has assistance for you when you are concerned about the violation of ethical rules. To be sure, I would run this by them. For what it's worth, I like your plan and I think TREC is mostly on the lookout for the unauthorized practice of law violations, and referral fees to unlicensed people - I don't see either here.
He should NOT use a quit claim deed. You may have problems with marketable title in Texas. He should use a general or special warranty deed. Contact a local attorney to prepare this document for you. It could cost as little as $100 plus filing fee. It is so worth it to have it done correctly up front.
Whose appraised value? Is it from the appraisal district? Independent appraiser? I would spend the money (approximately $500) for a new appraisal if you don't have one from an independent appraiser. He or she will factor in the life estate discount. You may be cheating yourselves because appraisal districts values are notoriously low and/or inaccurate.
You would need to read the documents. See if the apartment will remove the item from your credit. If they refuse, you can place the item in dispute with the three credit repositories: Equifax, Experian, and TransUnion. They all have websites.
It is against the law because it could be dangerous to her health - especially at this time of year. You will need to work through the appeal and if she doesn't get out then, you can request a writ for forcible removal by the constable or sheriff.
If he previously had no interest in his son, then the novelty will probably soon wear off and he will move on...again. However if you want him back in your life, then you can work visitation and boundaries out through your attorneys. Unless ex's girlfriend is a threat to your son's welfare, you won't be able to micro-manage ex's companions.