Draw-Tite Class II hitch # 36297 is indeed a correct fit for your 2007 Volvo V-70. This and other hitch options for your V-70 wagon can be seen on the linked page. They all fit all models of the V-70. Since you intend to use a hitch-mount bike rack I suggest you instead choose the Curt hitch # C12318 since it has a higher tongue weight (TW) rating of 350-lbs versus the others' 300-lbs. You cannot have too much safety margin. You will need to use a support strap # 18050 to help stabilize... view full answer...
As none of our hitch manufacturers offer a Class III hitch for your Volvo wagon, I'd recommend a Class II hitch like the Draw-Tite # 36297.
If you click the provided links, you can see the bike racks and cargo carriers available that are compatible with a Class II hitch.
For a cargo carrier, I'd go with the Pro Series 20x47 Cargo Carrier # 63155.
The # 70647 hitch you mentioned would not be a fit for your Volvo wagon. view full answer...
The Thule Snug Tite Hitch Lock # THSTL2 is threaded specifically for the Thule racks listed on its product page. This is the only locking pin offered that is for Thule racks. view full answer...