As far as CZ 457 action and barrel, you shouldn't be disappointed.
Whichever stock you go with comes with a lot of personal preference and maybe budget constraints.
The two models you mentioned if I am correct are really just separated by the Boyd's black laminate and the Manners CF stocks. With neither having a cheek rest it's hard to justify the coin for that Manners.
The Manners VPT - MTR, on the other hand does have a cheek rest and flattened forearm ready for an arca rail (if competition is also on your radar) but also the tippy top price.
I started down the rimfire rabbit-hole with the pro varmint, if you are cross training you will want a cheek rest to keep things as similar as possible. I eventually put mine in a chassis- which puts you up to the MTR price point (MTR did not exist for me at that time).
As always, it depends on how serious you feel about the rimfire thing. The spectrum being plinking to full-out competition and where you land in between.
But, of course, everything you spend for the CZ is forever with this rifle as that is the argument for the Rem 700 footprint variety.
The rimfire rabbit-hole.