I wrote this quickly since I haven't updated in a while so apologies if it's short or boring. (I was rewatching the seasons and playing RDR2.)

Tomura Shigaraki:

He will just let you be, not caring. If you want to annoy him, just blow the smoke in his face, he will be quick to glare at you, asking you what the hell you are doing.

Kurogiri:

He will glance at you whenever you light one with a look that says "that's bad for you" but never say anything about it. He will only say something if you smoke too many in one day, telling you he thinks you should cut down on the amount you smoke.

Dabi:

He won't care, he will even light them for you. He might even steal one for himself, but that doesn't happen often. He will sometimes eye you when you smoke one, finding you cool and sexy whenever you smoke.

Himiko Toga:

She will cringe and lean away, telling you that's bad for you. When you told her she's weird for finding killing okay but smoking bad, she huffed and said killing doesn't ruin her lungs or teeth.