Well it all depends how much of a perfectionist you are, I guess.. Given one has let it dry apparently well enough, and considering one anyways only vaporizes around 50mg of product to begin with, I think the amount of naphtha trapped in crystals is very small. People living in a city or painting a house are probably inhaling way bigger amounts of hydrocarbons regularly. I think most dmt smokers will be smoking crystals with small amounts of solvents and I think in general it wont be too bad (but then again, how much of the cases of people with headaches and other side-effects is actually because of petrochem traces?)
In any case, personally I am very picky, because Im just about to 'launch off to another dimension', I specially dont want to be inhaling petrochemicals when im doing it. Since a couple of years already I only smoke limo-extracted, fumarate-salted and water-crystallized-freebase anyways.. But even if not, I would make sure to remove those petrochem traces, and make my ride as smooth as possible.
As for traces of ethanol and acetone getting trapped in crystals, not really. Acetone and ethanol evaporate in a way that does not allow for big crystal formations like naphtha/heptane, therefore diminishing the amount of solvent trapped. Also acetone evaporates REALLY fast and well, which further diminishes chance of any traces. Lastly, ethanol and acetone are less toxic than petrochems, ethanol being drinkable as you know, and acetone being a compound present in small amounts in fruits for example and therefore the body being used to it in small amounts.
Heres one thing you can do: Get a small part of your stash and do the acetone/ethanol redissolution, and evap again. Then smoke that, in comparison to your normal crystals, and see if you prefer it in any way, or if you feel its a waste of time.. Decide for yourself, and let us know what you think
By the way, as I said before, acetone and ethanol dont allow for nice crystal formations, so if you care about your crystals looking good, they wont. It forms a very thin layer of crystals that can be waxier. Once you are evapping, at the end there might be some persistent drops that take longer to evaporate and dont smell of acetone/ethanol anymore, thats water that has been sucked from the air, just let it dry for longer and it will go away.