Quick question on brakes

Will linear pull or V-brakes fit on my Nimbus 36 with magura mounts.

yes, IF you buy V-Brake adapters. Most Bike Trials shops have some sort of adapters.

You can also get braze-ons, which some bike shops will do.

The adapters cost around $35, iirc. You may be able to find a used pair of maggies for less than that.