The short, not to technical answer is, it is ok to just change two tires on a CR-V, as long as you keep the same diameter tires on the same axle. All AWD’s are not created equal and this Honda is not a true AWD in the strict sense of the definition. The CR-V’s is really a FWD with occasional drive to the rear only when the front tires slip. So the rear wheels are just keeping your rear bumper from dragging on the ground most of the time. Now this vehicle is 14-15 yrs old so these can’t be the first new tires since the vehicle was new or are they? Do you live in snow country? That may be the most important consideration since Fall is around the corner and Winter not far behind.
A great set of fresh tires will do more to keep you on the road and safe and out of the tulies, than any AWD.