A couple of thoughts...

1. Playing as rogue is practical, but i prefer mage or, less often, warrior. I teach picklock to Zevran, he's mostly my character's LI, so easy to bring him everywhere. If not, then Leliana. One rogue good enough in the group.
2. Mostly spec myself, but sometimes I'm also too lazy for it. Especially with the rarely used characters.
3. What I found very useful, this is how the companions use his/her potions.

But I am not the most adequate: I have no patience to play in difficult mode.

I generally play warriors because they can be indestructable and immune to any knock-down effects. Which are easily the worst part of origins.

I used to use tactics and all other stuff to make my party the best, but that was before. Now I only play the game for the story, I don't want any challanges anymore after beating the game on nightmare

Well...

Leliana is kinda annoying and she's the only rogue you get until Zevran who's throat i usually slit sooo rogue it is lol

Also, the human noble has my favorite origin

I play rogues a lot too, (DW) because I like to fight up close and personal. I find warriors a bit too slow and also because of the lock and door picking thing. I also skill Zev to pick locks if I am not a rogue myself. Funnily enough, I was going through Jarvia's hideout with my current warden earlier (mage) and thought Leliana would be a better choice for detecting traps and picking locks but she wasn't. Before I went in too far I exited and swapped her out for Zevran and he detected the traps and opened the chests.

I don't auto skill the companions, I always choose them myself. I don't think I've ever autoskilled. I guess it's just that I think that it will set their stats and skills for things I don't want and I like to have control over that.

For the most part, no, I don't set the tactics. I also play for the story and fun. The only exception to that was the other day when I was going for my final achievement, which was to beat The Harvester in the Golems Of Amgaarak DLC on Hard/Nightmare (I opted for Hard, and boy was it ever!). I **had** to set tactics and micromanage the companions to win the fight. It would have been impossible without it. Now I'm back playing on Casual and I let my companions free range and do whatever they want. The most I will do is set how I want them to act, like with my current mage warden, I've got Wynne set to heal and apply buffs, so whatever that tactic's called. Alistair is set to be a defender, Zevran is a scrapper and his behavior is set to aggressive. But as far as setting each tactic, no. The Harvester was the only exception to that.

I love playing rogues, so I'm often the one who opens chest and locked doors myself. But if I'm playing a mage, I respec Zevran as soon as I get him, so that he gets the 'Open Lock' ability (and he is always in my party, Leli only, when I need her.
About autolevelling. I don't use it in any game, I like to control, what my companions can or can't do. SO I level them myself, it's not that complicated imo.
About tactics: I'm not that deep into it, but I usually have the warriors protect Wynne, my mage. Since she has to heal the others or bring them back to life (if my character isn't a mage and therefore spirit healer - the only mage spec from the vanilla game, I use tbh), Wynne has to keep us alive and therefore needs protection. So if someone is attacking her, my warriors are there to protect her. Other than that, I make sure, the companions use their important skills in situations, where those skills make sense. That's it usually. I keep track of the healthbars and give the healing potions manually, otherwise, they tend to use it all up without giving Wynne a chance to heal them.