Yes, all screws/mounting hardware is included.
None of the mounts on this page will be compatible since your scope has a 30mm tube and these mounts are for a 1" tube. For your scope, you will want MPN:26300, which can be found here: https://www.opticsplanet.com/dnz-dednutz-howa-1500-30mm-scope-tube-mount.html
Yes, this will work. You will need medium height.
For a scope with a 40mm objective lens you will need medium height.
You will want to choose one of the short action models. The height would be dependent on the objective lens on your scope. Please reach out to us at techsales@opticsplanet.com and we can provide you further assistance.
MPN: 12300 would be the appropriate mount.
None of these options will fit. Here is a link to the appropriate mount:
https://www.opticsplanet.com/dnz-dednutz-howa-1500-30mm-scope-tube-mount.html?_iv_ring-height=medium&_iv_color=black&_iv_gun-model=howa-long-action
MPN: 11300 would be the appropriate mount.
You would need a short action model.
MPN: 22300 would be the appropriate mount.