I have a few suggestions for candidate prisoners astronauts for this mission.

Such an intersting planet as well

https://www.reddit.com/r/pics/comments/y0xceg/the_clearest_image_of_pluto_captured_by_the_new/

Also a crewed Pluto flyby orbiter.

Perhaps Voyager 3 as 2 happened already.

https://www.youtube.com/watch?v=qYNIsgDrIRE

Although you might need to slingshot of Jupiter and Saturn at the right time.

It amazes me how our greatest minds were able to work this out with the technology and understanding they had.

It would be really difficult to design a spacecraft to go to Pluto and then return. You'd have to carry enough fuel to come to a stop at Pluto, then reverse back to Earth, then come to a stop at Earth. The extra fuel adds up quick because the more you carry, the more you need. A ship that could carry enough fuel for a round trip would be incredibly large and would have to be constructed in orbit rather than on the surface of the Earth.

You could reduce fuel requirements somewhat by going slower, but it already takes so long to get to Pluto that you'd soon be limited by human life expectancy.

So, a lot of the turnaround stuff for things like noon missions is done by using the gravity well of the planet and swinging back.

Apparently, the amount of nutrients and fuel required for even one person to be in space for a decade (assuming they’d live that long) and go that far would be enough to make the ship massive. At least double it if it you want to make it back.

To change the delta v of that fatty to turn around at Pluto would be an extra level of insanity. Also, there’d be like, zero boost there and that leg of the trip would be horrendous.

Not really. A gravity assist can be used to turn around the craft.

However, the craft needs to be slow (Pluto gravity is low) to turn around via assisted (via ion engine for eg) gravity assist. Moreover, it's near impossible to find a path that enables gravity assist to and from Pluto. Just one lineup of planets is rare, let alone 2 back to back

Given the long flight time, would the sample need to be shielded against radiation in order to keep it true to what you would find on pluto?

"kind of" does a lot of work here.