Which Alcohol profile should I use for dummyfiles?

Depending on the protection. What do you want to backup?

Well 2 of the 4 discs for The Sims Complete Collection are reported as “dummyfiles” with BurnOut.

I would try the safedisc profile.

based on the fact that disc 1 is safedisc? or should I use safedisc for all “dummyfiles” discs?

afaik sims ( sims 1 right?) has safedisc as protection. Dummyfiles are part of this protection. To go 100 % sure what protection is used scan the program .exe from the installation folder with protection id.
You can get it here