Is there any easy way to get all a rank for all teams?

I can help a little.

Team Sonic: All there mission's ranks are based on points, so get all the level ups, as many light dashes and multiple homing attacks in as possible. Also beat the level fast, most of the time the time bonus gives you the most points.

Team Dark: For their 1st missions, do the same as with Team Sonic. For their 2nd missions, time is the only thing that matters, so kill those 100 Badniks as fast as possible.

Team Rose: Same as Team Sonic, and since the levels are easier and shorter, and Team Blasts give Amy, Cream, and Big an auto level up, it's very easy.

Team Chaotix: The hardest of all. All there missions are based on score, so first play through the level to figure out where all the targets or items are, then memorize their locations, and try to beat them really fast. For other different missions, just do whatever fits you.

All Bosses: Time is of the only escence, so beat them ASAP.

GJS