so if we use numbers to accompany a noun - with the exception of number one the noun stays in singular?Would it be correct to say "Beş filler"? Or completely incorrect?
It is completely incorrect. If you have a number, there is never the plural marker. :)
There is a comprehensive discussion on this : https://www.duolingo.com/comment/7736911
Fil=فيل its arabic
The origin of some words in Turkish is foreign. The elephant is one of those words.