Welcome to the forum!
I think your Model Master acrylics will work on Deetail figures, though I haven't tried them that way, myself (I have Deetail horses for some 54mm metal riders), I've used them on metal, and on styrene.
The key will be in surface prep, whatever paints you use. I would wash the pieces in warm water, with a drop or two of dishwashing liquid added. I scrub pieces with an old, soft toothbrush. That will remove any mold release compounds that might still remain, skin oil, other dirt, that can interfere with adhesion.
Then prime the figures. There are as many opinions on priming and primers as there are painters. My own preference is to use autmotive primers, and I buy Walmart's store brand. It costs much less than primers like Tamiya's, and I've found that it provides good "tooth" for the finish. I've also used Rustoleum's primer, which works just as well, but it costs about twice as much as the Walmart brand.
Let the primer dry and cure, according to any instructions on the label. Then you should be ready for your finish colors.
Regarding the brand, I'll say that I've got Model Master, Tamiya, Testor's and even the 99-cent bottles of acrylics sold at Michael's and AC Moore. I use oils, too, for some applications. If you don't already have a favorite line or lines of paints, try different ones and you'll come to decide which ones you like best, ie, are easiest to use and produce a good result, to your eye.
Hope that helps, prosit!
Brad