The Galco D.A.O. Holster for Ruger and S&W Handguns may fit a Smith and Wesson model 629. However, for that gun I recommend using the Galco Dual Position Phoenix Holster at the link below.
https://www.opticsplanet.com/galco-dual-position-phoenix-holsters.html?_iv_parent-gun-model=smith-and-wesson-model-629&_iv_gun-model=smith-and-wesson-model-629-n-frame-revolver-5in&_iv_gun-make=smith-and-wesson
You would be able to use the 686 6" Galco D.A.O. Holster. There will be an inch of empty space but your revolver will still fit.
I would recommend reaching out to Galco directly to confirm fitment, but I believe the Super Redhawk 5.5" holster will work for your revolver. MPN:DAO178
No, these only go up to 6" barrel.
No this holster will not for your Rossi 720.
No this item will not fit your Ruger Redhawk. The closest option is for a 5 inch barrel not the 2.75 that you currently have.
Unfortunately Galco does not make a version of this holster that will fit your pistol at this time.
This holster will work with belts up to 1 3/4", so it should work with the belt you have.
Galco does not currently offer a left hand variant of the correct holster for your revolver.