Yes, MPN: 171498 should fit for your Howa 1500 HCR in 6.5 CM
The Short Action Remington 700 Leupold Mark 4 One Piece Scope Mount is made of steel.
The Leupold Mark 4 One Piece Scope Mount for Remington 700 Short Actions will work with the B14R. The base at the link below will also work.
https://www.opticsplanet.com/bergara-ba0008-20moa-rail-rem700.html
Yes. The Leupold Mark 4 One Piece Scope Mount that you can use for your Savage 112 is MPN:170746. You can also use the Weaver Extended Multi Slot Base found using the following link:
https://www.opticsplanet.com/weaver-extended-multi-slot-base.html?_iv_gun-model=savage-model-112&_iv_code=WR-WPM-EMSB-99489
Yes this would work for you.
No, this will not fit.
Yes, it will.
Some of the mounts will need to be installed with the cutout on the proper side.
Yes, the optic should work just fine on the rail with the proper scope rings.
Leupold does not mention a recoil lug being included.