Lone Wolf on Tactician is gonna be rough, especially without Glass Cannon. There's a bunch of fights that have immune to physical/immune to elemental mobs. Totally doable, but yeah you'll want to keep various types of wands and a good amount of grenades for your warrior.
You can but the option comes fairly late, unless you rush for it which requires decent knowledge of the game.
Finally finished Cyseal, last fight was way easier than I expected, I thought the tactician change would make it crazy but it's like zzz stuff, and I feel the boss was even nerfed since I don't remember debuffs sticking to him that much, I had like 8 different debuffs on him. Didn't notice after the fight I had enough skill points for 5pt dual wield either. Finally done with that, now I can invest in Scoundrel and learn all those stupid books I've been carrying for 4levels.
Melee rogue is definitely different, and not nearly as OP, but I find it pretty strong still. And I get to use skills and stuff, rather than just mash sneak backstabs.