>That's a bit of a straw man.

Not at all, the current state-level bans on private sales only make exceptions for immediate family members and a few other specific groups/situations, they would make the behavior in my questions a felony.

Here's Washington State's exceptions (note that c would not apply to my violent ex scenario because the violent ex would need to be actually present at the time of the transfer and threatening harm):

(4) This section does not apply to:
(a) A transfer between immediate family members, which for this subsection shall be limited to spouses, domestic partners, parents, parents-in-law, children, siblings, siblings-in-law, grandparents, grandchildren, nieces, nephews, first cousins, aunts, and uncles, that is a bona fide gift or loan;
(b) The sale or transfer of an antique firearm;
(c) A temporary transfer of possession of a firearm if such transfer is necessary to prevent imminent death or great bodily harm to the person to whom the firearm is transferred if:
(i) The temporary transfer only lasts as long as immediately necessary to prevent such imminent death or great bodily harm; and
(ii) The person to whom the firearm is transferred is not prohibited from possessing firearms under state or federal law;
(d) A temporary transfer of possession of a firearm if: (i) The transfer is intended to prevent suicide or self-inflicted great bodily harm; (ii) the transfer lasts only as long as reasonably necessary to prevent death or great bodily harm; and (iii) the firearm is not utilized by the transferee for any purpose for the duration of the temporary transfer;
(e) Any law enforcement or corrections agency and, to the extent the person is acting within the course and scope of his or her employment or official duties, any law enforcement or corrections officer, United States marshal, member of the armed forces of the United States or the national guard, or federal official;
(f) A federally licensed gunsmith who receives a firearm solely for the purposes of service or repair, or the return of the firearm to its owner by the federally licensed gunsmith;
(g) The temporary transfer of a firearm (i) between spouses or domestic partners; (ii) if the temporary transfer occurs, and the firearm is kept at all times, at an established shooting range authorized by the governing body of the jurisdiction in which such range is located; (iii) if the temporary transfer occurs and the transferee's possession of the firearm is exclusively at a lawful organized competition involving the use of a firearm, or while participating in or practicing for a performance by an organized group that uses firearms as a part of the performance; (iv) to a person who is under eighteen years of age for lawful hunting, sporting, or educational purposes while under the direct supervision and control of a responsible adult who is not prohibited from possessing firearms; (v) under circumstances in which the transferee and the firearm remain in the presence of the transferor; or (vi) while hunting if the hunting is legal in all places where the person to whom the firearm is transferred possesses the firearm and the person to whom the firearm is transferred has completed all training and holds all licenses or permits required for such hunting, provided that any temporary transfer allowed by this subsection is permitted only if the person to whom the firearm is transferred is not prohibited from possessing firearms under state or federal law;
(h) A person who (i) acquired a firearm other than a pistol by operation of law upon the death of the former owner of the firearm or (ii) acquired a pistol by operation of law upon the death of the former owner of the pistol within the preceding sixty days. At the end of the sixty-day period, the person must either have lawfully transferred the pistol or must have contacted the department of licensing to notify the department that he or she has possession of the pistol and intends to retain possession of the pistol, in compliance with all federal and state laws; or
(i) A sale or transfer when the purchaser or transferee is a licensed collector and the firearm being sold or transferred is a curio or relic.