was informed that our sun is estimated to be 24 trillion miles away
No, the Sun is 93 million miles away (averaged over the year, as our elliptic orbit continually changes the distance).
and that it takes 8 minutes for the suns' heat to reach the surface of the earth
I'd say light, not heat, as it is the light that carries the heat (in a real bastardisation of the terminology) but yes, 8 minutes.
So if the closest star is 24 trillion miles away
Ok, the Sun is 93 million light years away. The next closest star, Proxima Centauri, is 4.3 light years away. Speed of light is 186,000 miles per second (don't you just love these Imperial units!). So 4.3 x 365 x 24 x 60 x 60 x 186,000 = number of miles = 25 trillion miles. But this is 4.3 light YEARS away, not 8 light MINUTES !!
how far away are these other stars that it should take, say, 100,000,000 lightyears to reach us?
A light year is a distance remember, so you mean "100,000,000 years to reach us". 100 million light years is a long long way outside our Galaxy. Our sister galaxy, Andromeda, is only 2.2 million light years away. The stars we see at night are typically from 10s to 1000s of light years away, all contained within our own Galaxy. The Galaxy is rougly 100,000 light years across, but we can't see too far through it becasue of dust, although we can use infrared, radio and x-rays to see further.
Does any of this mean tht light did in fact travel in the past? Certainly not, however, we at leaset know that it is possible, proven undeniably by two separate teams.
No. Despite the popularisations of these experiments, they have NOTHING to do with "c" the true speed of light. The experiments are certainly interesting, and in the latter case extremely useful, but they have nothing to do with the speed of light. They deal with the speed of phases of light, which is a wholly different thing.
These studies lead a legitimate inquiry into how we percieve the parallax of starlight.
Not in the slightest, for the reasons mentioned above.