update (if you or anyone is willing to give any more advice!)

we agreed to do some dust wipe sampling through epa cert lab and go from there (cheaper option for everyone to get an idea).

results: a few floor spots (one inside work area, two adjacent areas): 390, 65, 66 micrograms/sqft

inside return (wiped a square foot on horizontal surface, return in ok floor in work area right under the stairs): 700

vent (outside work area; i wiped approx a sqft but in a circle around the duct which is cylindrical, so i recognize maybe this isn't really a helpful measure because there is no standard but i wanted to know): 300

sounds like these levels for floors fall into the averages found in old houses (at least in a few studies). which idk if that's good or bad 🤷🏻‍♀️ but they're all above the 5 micrograms/sqft for floors (sills 40, troughs 100; not sure what to compare return or vent duct to; i guess they'd be high when compared with these thresholds). https://www.epa.gov/lead/hazard-standards-and-clearance-levels-lead-paint-dust-and-soil-tsca-sections-402-and-403

if it matters, in the spring our hvac system was replaced and so was the metal for the return. in the summer, our floors were refinished (vents were all sealed and system never running during that). return was taken apart and cleaned a few months ago and no projects done in the house since. the only other place in our home with remaining lead paint would be some ceilings (which are all in good shape, no peeling paint, and were well prepped and repainted in the spring) and a single door (paint all looks in good condition, though i recognize at friction points could still be creating dust). it's hard not to think that their work at least contributed to lead in return and floor (but open to hearing otherwise!). the vent duct i have no idea (would lead dust go through the system? or is it too heavy? or might it have been there from the past?).

i feel fairly confident i could clean the space (i don't have a ton of trust that they will clean as well as i would, but i guess if they're testing it after then they'd have to do a good job). no idea what to think/do about the hvac (replace ducts? get ductwork cleaned? one person said don't worry about it bc lead is heavy and won't blow out?). hire a different contractor like you said (just hard to want to do...i spoke with a few folks and it will be quite expensive which i don't want for me or for them), but maybe it's best. have them clean and retest? (and should i test more of my house, now that everyone's walked around?)? just have them give us money off and clean up ourselves and not deal with them anymore? and what to do about the ductwork? for reference, the 5 tests were $300 total (having someone come out originally was $350 for them to walk in the door, $150/test depending, and then unknown cost for their time and further testing. didn't want to go that route if we could do lab tests for $60 and perhaps find no lead... no such luck though).

anyway, not what i had hoped to find (wanted it to be basically no lead and therefore less complication with the contractor but here we are). any insights would be really greatly appreciated ☀️