Tomatoes will grow pretty much anywhere anytime, until it freezes. A lot more slowly if it's cold. Fruit won't set below 50F, may set funny below 55F, and the whole plant is weakened at low temps. But they'll grow. In fact, tomatoes are somewhat perennial, so if you can get them to survive the winter, I'm told they'll rejuvinate and produce in the spring. That being said, if temps are below 40F, I suspect seeds won't germinate at all.

I have been told tomatoes need so many hours of light to be productive which is why they slow down in the fall.

I interpreted the question to be about whether the PLANTS would grow in autumn. They will, but not much. As noted, for several reasons, it's unlikely that there will be any fruit.

What if I brought them inside and put them on a windowsill?

Well, you mean like a houseplant? Sure, they'll be green, they'll probably get leggy for lack of much sun, and they won't fruit, but there is no reason why they won't live. Not entirely clear what your goals are here. If you're practicing gardening skills, you might be better off doing different things than starting tomatoes in autumn. You don't say where you are (I have to assume southern hemisphere), but there are likely better things to plant outside at this time.

I live in the Deep South, where, theoretically, we should be able to raise and harvest tomatoes in the ground well into the fall. However, my experience says otherwise. When our high temps climb above 90 and stay there, the plants stop setting fruit. We have a lot of soil borne diseases that take a toll on the plants, as well. Once the temps fall in the late summer and early fall, the daylight is less and less. They don't like that. Then add the increased insect pressure of fall and I have had very little luck with tomatoes. On the other hand, I have had very good luck with growing hybrid cherry tomatoes in pots from spring all the way to late October or early November. I think it's because the soil is disease free and I give the plants daily inspections as I water. AND, I fertilize them in the pots at least once a month. For my main crop, I plant as many plants as I have room for, can them and pull the plants out by mid July. (but continue to nurture the 3 plants I put in pots.) I then plant something else in those spots that can take the heat: okra, cowpeas, etc. What will do for you depends on where you live.