Excellect!!! Thank you.Mr. Primer is proper primer, intended to improve adhesion of the paints that go over it.
Mr. Surfacer is thick (the lower the number, the thicker it is) and though you can use it as a primer, it's really intended to either add texture (by, for example, stippling it with a brush while it's still wet), or to fill minor imperfections so you can sand it down to hide the imperfection.
Mr. Base … your guess is as good as mine.