Are all of these fonts TTF, if not how do I know if they are TTF fonts? Thank you

They are truetype and/or opentype. Both will work for you.

Under the large red rectangle where there is the font name, you can see a grey rectangle with the file name. The file extension is also shown, so you can see if the font is a .tff file. Sometimes though, it only shows one version of the font: there could be more inside the .zip file you will download.