Usually there is not much difference between brands with epoxy primers ,some are thicker and require more reducer or have slightly different sheen when dry.As for Basecoat,Nason is the lowest of the low IMO,requires 5 or more coats to get decent coverage,while Wanda,Matrix,Pro-Spray do it in two coats.I like using Matrix and Wanda base and Matrix AG-40 High-solids clear.I use Evercoat G2 primer.

There is absolutely nothing wrong with mixing brands, I've been doing it for well over 20 years and guarantee my work for life,if I had problems, I wouldn't mix brands or wouldn't warranty.