Even though a Barbarian can potentially obtain the highest magic find possible of all characters, this is a VERY, VERY expensive build, one that shouldn't be done until you get some decent items that you can trade for your barbarian's gear. I believe if you're going for a MF barbarian, that requires using the "Find Item" skill where you're expected to carry dual Crystal Swords with 6 Ist runes in each along with other expensive components. Since you really can't kill anything with two Crystal Swords, you also have to gear up your mercenary to the point where it can kill monsters in hell easily (usually good enough to kill Hell cows if you're hunting for items).
Of course, that is slightly overkill - you'd be good with a Barbarian (or any other magic find character build) with around 300-400% MF, as increasing your magic find results in diminishing returns. However, since a MF Barbarian is considered a luxury build, you usually want to max out your MF.
Personally, every time I start over in Diablo II I make a Sorceress as my first character to magic find, and then go with a more expensive character (such as a Paladin) once I have better gear, but it all depends on what sort of Paladin you're planning on making, and how you're planning on playing the game (solo, multiplayer, what you're doing with your character, etc.). While pumping about 75 hours into your Paladin to get to level 90 is nice, that is no guarantee that you will have good enough items to solo Hell by yourself.
And as for your last point, it is equally dangerous to self mule with any character. Transfer at your own risk :).