I know that they will grow rapidly, but right now my nodes are fairly close together.
Will they stay the same distance apart and create a nice cluster or will the stretch further apart as they grow during flowering?
It all depends on how close your light is. They will not expend any more energy than necessary so if the light is close, the nodes will remain close too. Look for them to triple in height during flowering.
Yes they are Indica for shure you can tell by the wider leaves. The nodes being close together have more to do with genetics apose to light. The light does have some say so. usually breeders look for plant genes with closer nodes sighn of good genetics. They usually produce more and make great indoor plants cause there short and stout with plenty of nodes to flower.