would it be possible to create a mini neutron star, let's say the size of a baseball?

No, neutrons are unstable. They decay into a proton, electron, and neutrino with a half life of 15 minutes. Only strong gravity can overwhelm this decay process.

if we peel off all the electrons and protons out of the heaviest atoms it would result in a neutron mass.

My understanding of neutron stars is that they are the result of a star that has expended all of its hydrogen and helium, its outer layers explode, and the remnants collapse in on itself to form the neutron star.

However it is a delicate balance. Too much or too little material and the result is a black hole, not a neutron star. So forming a neutron star that small would be very difficult, maybe even impossible.

"Possibilities" are only limited by current knowledge and technology.

No, a mini neutron star is not possible. Not now, not ever. Not unless we can do magic. We might, some day in the very far future, be able to make neutron stars as small as 5 km radius. Anything smaller would not be a star, by any reasonable definition. Except for black holes, which have been called "frozen stars" and "collapsed stars".

Yes of course! In fact most neutron stars are so dense they aren't very big