You have the wrong idea about liches. They only need to stick their soul in some object for a time being during the lichification process. Once they're a lich, they have their soul back into their undead and decayed body.

At least that is 1 known method. But all liches still have their souls when they're walking about.

Well maybe some liches are forced to be bad except that Logren Benirus guy, he's bad...

Then again, Liches are like the lords of the Underworld so who could force them?

I get what you mean, but it is similar. I bet that is how the author came up with the Voldemorts immortality subject.
Anyways, No, liches are not evil, there are only shades of grey when it comes to power. It depends on weakness of character or thirst for power that will drive anything to be evil, which in itself is basically just the opposition one side faces. For all we know, the Nine could be evil. In terms of religion, I think it is an evil although a necessary one to keep people in line

Lords of the underworld? No such thing, except for Shor in Nordish myths, who is Lorkhan who is Shezzar