If I have a flier with divebomb that has ambush equipped as well, if the opposing figure is standing next to hindering terrain can I divebomb(-2) into the hindering and use ambush(+2) to cancel the effects and get my original attack back when I hit?

Divebomb allows a figure to make close combat attacks against grounded figures when it is soaring. There is no terrain at soaring level, so a soaring figure can never occupy hindering terrain.