I think the word you were looking for there is finite. 495 is a finite set of positions. Countable sets can be finite or infinite, but an infinite set isn't really what you were going for there.
"He ran less quickly when he heard the bear slow down behind him."
Is "quickly" there somehow divisible as "finite" or "infinite?"
As opposed to...
"Bears are sprinters, not marathoners. If you have only run three or fewer miles, then they will still chase you, but after that, you should be okay."
Substitute "less" for "fewer" above... it might be something you say in colloquial conversation, but it is not technically the right application of "less."
"Fewer" would be better because it is one two three miles.
This is not really a mathematical question but a grammatical one between the use of "fewer" versus "less," where I do think something being countable/quantifiable is really the determining factor about which one is appropriate.
I just did the nCr exercise to be funny afterwards, but I think my point that 495 is not such an infinite or uncountable number where "less" would be appropriate.
But, the original question was about the total number of candidates. While that is also finite, it is significantly larger than 495. In this case, I'd say that your population is the number of athletes in the transfer portal and the sample size is the number of open scholarships we have.
I agree with you on this point, however. The discreet population of 12-13 men on the roster versus the whole universe of potential transfers is quite different -- the former is easily countable, but the latter is amorphous in its true size.