Good news you can make this work!
I'd go with the Yakima HullRaiser Aero kayak rack first of all. It attaches directly to your 2007 Toyota Rav4 factory rack crossbars. No need for any adapters either. The great thing about the Yakima HullRaiser kayak rack is that it uses up very little crossbar space because the kayak is carried semi-vertically on its side in the j cradles. You'll then have plenty of room to add a bike rack to the Toyota Rav 4 car rack bars.
FYI Yakima Racks has a very cool new product called the
Yakima BowDown kayak rack, which works exactly the same way as the Yakima HullRaiser Aero except that the Yakima BowDown allows you to fold the upright cradles down when not in use so there are no possible overhead clearance issues when pulling into garages or low-overhang entrances. Attaches directly to your factory rack bars too.
FACTORY RACK BIKE RACK SET UP
UNIVERSAL MIGHTY MOUNTS
I then recommend buying a set of the Yakima Universal Mighty Mounts for use with the bike rack. The universal mightymounts clamp right onto your factory rack cross bars. You can then attach any Yakima Racks upright mount bike rack to the set of Mighty Mounts. The MightyMounts will only let you attach an upright mount Yakima bike carrier (the type where you keep both wheels on and simply place the entire bike onto the bike tray and then clamp the bike down on either the bike frame or the front wheel, depending on which model bike carrier you decide to go with). Not compatible with fork mount bike racks (the type where you take the front wheel off first and then clamp the bike forks into the fork block on the front of the bike tray).