By redeem? Do you mean reincarnate to atone for sins? No, there's no limit, but there are side effects to removing the felonies count to your character's name, i.e. less influence in the dark assembly so it's usually a good idea to keep at least one character (i.e. Adell) with the 99 felonies mark.

Not sure about your second question. Do you mean the specialists that appear in items? They grant bonuses and special effects. Topic is way too expansive, so you'll have to just wiki "specialists disgaea 2" a bit unless you have specific questions.

Yeah, you can "Reincarnate to Atone for your Sins"/"Reincarnate into a Prinny" bills, though there's little reason to do them. The only downsides of Felonies are that the characters with those can't be ascended/sacrificed to the Dark Sun (a mechanic on certain postgame stages, kinda like a sidequest), which you rarely if ever want to do anyway, and... the ugly stamp on the character portraits, which is just cosmetic. On the other hand, felonies gives discounts in shops (I think they have to be on Adell or Axel), makes passing bills easier for the character who has them, and, more importantly, makes your character gain more EXP. You can get up to 300 felonies for the max effect, though the displayed felonies on a character's portrait caps at 99.

Felonies also serve as flags for certain events to happen, like unlocking certain bills or triggering the bad endings (though you also need to kill your own allies a certain number of times, so you don't have to worry about that. And even if you do get lots of ally kills for some reason, you can use the aforementioned bills to prevent the bad endings).

When farming Felonies, it's recommended for you to make a tower of characters and throw them into the gate, so you can get felonies for 9 characters at once. Prioritize giving felonies to humanoid characters, as you'll unlock a mechanic later on that allows monster units to partake on the benefits without having the felonies themselves.

Also, I'm not sure what you meant by "items with names to the side". Maybe subpoenas, where the bailiffs are? You usually want to transfer those bailiffs to another item you want to raise or get the specialists from and just sell/discard the subpoenas. Or maybe you mean "specialists" (aka "innocents") in general? Those are random "traits" from the item, like giving an item more ATK, HP etc or some other benefit like giving a chance to inflict status ailments on enemies or receive more HL after a battle. To change them from one item to another, you need to subdue them (find them in the item and "kill" them), which is indicated whether the little face in the item is angry-red or happy-yellow. Subduing them also doubles their value, which basically just makes them stronger/more efficient. You can check what each of them do with this list[disgaea.fandom.com].

thank you neemoos and Icarus the second question was about specialists