At the beginning, you just need cleaving finish, which you achieve in the prologue.
At this level, you don't have a better choice anyway.
Up to level 10, there aren't many sensible rogue talents you want to pick anyway.
You can unlock outflank at level 6, shatter defenses at level 8 at the earliest.
Until then, you have one extra feat that you can spend on anything.
After level 8, good feats start to end and you still have at least 6 feats (basic only) to spend.
From this you would definitely take improve initiative and improve critical.
Alternatively, you might want dreadful carnage, the problem is that it requires level 15 where by this point one of your characters should already have a frightful aspect.
Only if you play Human (which is it's own cost on a class that already gets a ton of skill points) and take Power Attack and Cleave then Cleaving Finish at lvl 3, which means you're not taking Focus there, which means you're blowing your first Rogue Talent on it if you want Outflank and Shatter on time. You're a 3/4 class with the Power Attack malus and no way to boost AB if you go that way. Vital Strike/Big Sneak Dice can mean not needing Power Attack at all which frees up a lot of room to take advantage of the other strengths of the class (and climb out of the hole of your low AB).
Exotic Fauchard is something you could take at lvl 1 to widen your crit range (though that wastes Martial) and/or you can pick up Blind Fight/Improved Initiative upfront to benefit from them the whole game (gaze immunity for Market Square Nabasu Fight, reroll vs tough foes with Concealment). If you're going to be covering Stealth for the party will need Skill Focus to pass checks on overland map in ch 3 where you really don't want to get ambushed.
A lot of good options there if you don't burn all your Feats on AoE that isn't that important if you've got an Archer or two with Cleaving Shot (or you can just use Wide Sweep of course). Other classes support Cleaving (and Intimidating) better.
Unlike kingsmaker in wotr, I've never used blind fight. The only enemy I regretted about it were retrievers, but nothing that can't be solved with a skeleton army (it's a pity that the AI is worse than in BG2).
Rowdy is the only archetype that gets 3 skill points per level at 10 int.
Outflank should be unlocked at level 6 which means that if you don't spend your rogue talent you won't be able to choose it up to level 7 which is a big loss.
The problem with weapon focus is that when you should unlock it depends on the weapon you choose. There is no point in taking it that fast if you don't find any weapons up to level 4-5.
No matter what weapon you choose, at the very beginning you will most likely be using a glaive, which automatically makes you have +1 from the book.
If you are going str you are unlikely to get enough stealth to actually make a difference.
Even so, you have other characters that can do this, if you choose Lann, the problem solves itself. It is worse with Wenduag.
Recently, I liked giving her lvls in a wandering markman.
I know that it is quite suboptimal, but i really dont like basic fighter. It makes the early game much easier.
Unfortunately her wisdom, aligment and deity narrows down meaningful choices quite a lot.