You can definitely mix and match. Films are generally "calibrated" to develop well with Kodak D-76 (and equivalents, e.g. Ilford ID-11 which is functionally identical), but they will tend to work in a broad variety of developers. My main developers are by Kodak, Agfa and no one in particular (the latter being PMK, which is a publicly published formula by Gordon Hutchings - you can buy it premade from a couple of sources, or get raw ingredients and make your own).

As for Arista films, they are made by whomever Freestyle gets their film from - which in the past has included Kodak, Fuji, Ilford, Forte, Foma and probably other countries. I can never keep their different levels of film straight, but if you find out where they are made, you can figure out who made them. Kodak is USA, Fuji is Japan, and Foma is Czech Republic. (Freestyle doesn't rebadge Ilford film anymore, and Forte is out of business.) The Kodak- and Fuji-made Arista films are terrific as you'd expect, although I'm not sure they are available anymore. The Foma stuff is the easiest to get from Freestyle, and while it's grainier than Fuji and Kodak and Ilford, and it's a little more delicate, it has a tonality to it that many (including I) enjoy.