Bipole vs Monopole Surrounds for Gaming

Ideally, gaming wants all 5 channels to be exactly the same. They aren't doing any fancy mixing, they are simply positioning audio at 360 degrees and reducing down to X number of channels. As such, 5 matching speakers is ideal, that way a gunshot in any location sounds exactly the same regardless of which sound-hole it's coming out of. Bi-poles's will diffuse the rear channels creating a wider area of coverage and larger sweetspot at the expense of locational accuracy.

Bi-poles were great for the ProLogic I days, but don't have much of a place in a modern home theater unless you are doing something odd like two-level seating or something.

Corner placement aimed at the half-way point between the chair and bed, or facing forward toward the wall with the monitor on it would be the two options to look at.

Does the receiver that you are driving these from have Audyssey MultEQ on it?

As far as wall mounts, I have no idea. Monoprice would be the first place I would look for a cheap, sturdy mount.

Then yes, angle the speakers to the halfway point between the chair and bed, then run MultEQ setup with the mic in all 6 positions starting at that midway point, then the center of the chair, center of the bed, then a couple points where your head ends up when you lay on the bed while watching a movie.