1. Look for pipe hangers in the plumbing section. Can either get a rigid curved bracket that fits around the center nut, or more flexible metal straps to go around the manifold body. Either way, can screw them directly to the wooden collar.
2. I'd pick up a new barb for your regulator, or a short length of 1/4" gas hose for the section joining the manifold to your tank, especially if you plan on quick carbing at higher pressures. Connections that seem fine at serving pressure of 8-10psi can let you down when you crank it to 30psi. Whether you use the gear you have or pick up new parts, make sure to leak test all your joints at the highest pressure you plan to use, either with soapy water, or with actual leak detection solution from a plumbing supplier.
3. Welcome to the forums, and congrats on the keezer. Make sure to post pictures