It is normal for some bios to refer to a DVD/BluRAY drive as (ATAPI CD ROM)
Nothing to Worry about here.
Where are you getting 20 and 64Gb from??? Win 7 should be just less than 4GB (at least for Home Premium x64)
Im confused... are you trying to do a clean instal with the original Win7 DVD
Re-Image a previous Image of the set up (like with Acronis or Macrium?)
If it is a Image you burned to a BluRay disc, you will need to boot your machine from the rescue disc you created from which ever program made that Image. I/E Acronis, Macrium, paragon whatever.
When it asks for the Image location, then insert your Bluray Disc that contains the image and point it to the CD Drive again.
As far as the iso, it may depend where you got it. But if you got your copy from somewhere such as the MS Store, you can DL and burn it as much as you want. Im not aware of any 1 time limit.