During the summoning phase, do I only have to place a figure in a legal board region when summoning a figure normally or does this apply to chaos cards who allows figures to be summoned?

If I understand your question, if a card tells you to summon a figure to a location, then you can do so even if you don't have other figures nearby/in bordering regions.

So a card can summon a figure from the other side of the board (or from your reserve) even if you have nothing else close.

Yes, this answers my question. Thank you!