Check the underside of the leaves for any webbing, to me it resembles spider mite damage (best guess). Google up images of SMs on tomato plants for comparison.

I just now noticed what appears to be tiny mites on the lower pic's leaves (little beige colored specks, esp on the left).

tomatoes are not really house plants... and it wont be easy trying to make them such ...

so there could be a myriad of issues making the plants weak ... allowing for an infestation of other problems ...

if they were outside .. how did you 'clean' them.. before you brought them in ... in case there is another try next year ...

have you isolated them yet??? ... you dont really want to spread this to all your houseplants ...

how do you plan on caring for these absolute full sun plants indoors all winter??? ..lights.. humidity ... outgrowing the small pots they are in .. etc ...

im sure there is something there.. but im not convinced you can 'see' a spider mite.. in a pic ... or im wrong.. whatever ... lol

it will be a fun experiment.. and you will learn something for sure ... but dont get upset.. if you fail .... the learning is for next time ...

ken