None of them are actually all that "easy" if you do a good and thorough job - but some are a lot harder than others. The Huntsman (and likely the Sidekick) as well as the CVA Optima has an area that is basically 'uncleanable' unless you do a complete breakdown of the rifles. That area consists of the firing pin and whatever is behind it. The T/C Omega would probably have to be the "easiest" but it has drawbacks for some (me included). The CVA Kodiak and the Winchester Apex may be equally easy to clean but I have no experience with them. Bolt action muzzleloaders (not plunger action) tend to be the most time-consuming to clean in my experience. The Savage is the likely exception since it uses smokeless - my guess is that - with BP or subs - its cleaning is also time consuming.

My overall preference in the available rifles would be among the break-opens with the T/C varieties leading the pack. But nobody has built me a Ruger#1 muzzy yet. Henry???