Baby Dreads unravel
Yes, it will effect how they lock. It'll make them lock better. New locks should always have about 2-3 inches of loose hair at the roots. That loose hair allows your hair to move around freely. This freedome lets them tangle and knot. If it was done too tight, they would have nothing to grab onto as they grew out. PLus they;d stick up looking like Sideshow Bob.
Take the bands out. Bands only hurt your locks. At best, they will just restrict movement and stop the from knotting. At worst, they can break off and get sucked into your hair and start to rot inside causing mold and mildew. Bands also are too tight and pinch your locks causing weak spots.
If you want to keep them sectioned off, you can use beads or wraps. Beads are better because they move freely and act like little knots. Wraps are ok, but restrict movement more.
As for how many and how skinny they are... Baby locks are always thinner than they will end up being. 27 is going to give you some pretty hefty locks. When they mature, they'll end up being roughly the size of the sections. You probably don't realize it, but I'd guess your sections are probably about and inch or more for most of them. So your locks will be about the thickness of quarters of even thicker. If you don't want them to end up this big, you can take them out, and redo them before they get too far along, and you lose all that progress. It;s easier to combine 2 locks than it is to split one into 2