I didn't take any of the personality skills as a major skill and was wondering if it was possible to get +5 attribute gain with just minor skills?

Yes, of course, it works just fine - doesn't matter whether major or minor skill for ability count. You still need to up major skills by ten points to gain a level though.

forgive my ignorance but I've been attempting to level by 5/5/1. So I would level one major skill with 10 points instead of 5 points of two major skills, ie 10 points on any major 10 points on minor personality and 1 point on luck.

Well, 10 points in any of the three related skills for one attribute, another ten in any for another, with only ten of those twenty for major skills. For example 3 in blunt, 5 in hand-to-hand and 2 in blade + 5 in heavy armor and 5 in block with hand-to hand and block / heavy armor and block / blunt, blade and heavy armor as possible major skills combination. + some other points in any minor skills accidentally taken, but not in major.

Gotcha, Thanks a lot Sarya!