I posted in that thread about playing with just one character and it is possible so far, I'm currently in hiberheim on hard. I said that I was using leech but I ended up starting over to remove leech. I'm using a cleric with hydro and man at arms. I started with lone wolf and thick skin. I'm not using leech, zombie or comeback kid. I mention those because I know some people think they can make your character a bit too strong when paired with other skills and abilities.
The second main character just sits in town with a pyramid next to the vendors so I can get back to them quicker. I haven't used him in combat at all. I also haven't given him any crafting abilities, I'm trying not to use him in any significant way. I only teleport him to me when a puzzle requires a second person or when traveling to a new location as you can't enter certain dungeons or even the homestead without him.
In the beginning when fighting I would use line of sight to my advantage and kill one or two enemies then retreat heal up and go back for more. I also pulled a couple of the close groups to town so I could use the ballista and the guards ended up helping. Later I killed the guards and no name npc's for extra xp. After winning rock paper scissors I would still fight the person so I get more xp.
It's tedious and slow going but it's doable. Lots of Qsaves and Qloads. Once I got half way through the forest I could pretty much take on the group or most of it without retreating. Using water of life and water shield before engaging. Pulling enemies around a corner so they have to group up next to me then using an Aoe ability or scroll. The enemy mages and archers would also hit their own allies with aoe which was helpful.
To comment on what Shaki said, that's really all there is to it at least for a melee character, high block chance and high resist. Add that with an elemental shield and heals from hydro, arms, and even potions and it's not too hard just tedious.
TLDR: It's possible so far, I'm in hiberheim on hard.
