Right now...
My character is summed as '18 strength and punches people' right now, as none of us are very unique yet without levels. I'm unarmed, so that means bludgeon/stance damage and a free hand to mess with people.
I'm good at totally immobilizing enemies who aren't very large or very strong (and I can grapple two enemies at once I think, and still attack?), making them prone, immobile, flatfooted and restrained. This means in order, -2 to attacks and defenses vs melee attacks, can't move, and in the case of restrained can't do anything. Prone enemies are really slow unless they spend an action standing up. Grabbed foes also have a flat 25% chance of failing to do anything. I can shove foes around and bully them about the battlefield, protecting squishy people vs AoO abilities, dropping people into flanking positions, or just tossing them off cliffs. I can also disarm people of their weapons, shields and held items with some success. In turn I am harder to push around or disable.
My combat style is designed for doing full attacks against flanked enemies, doing +1 damage on the 2nd attack, and +2 damage for the remaining potential 2 attacks. Though in turn, spamming that many attacks means not many are going to hit at low level.
Out of combat, I am good at climbing, swimming, breaking things, carrying etc. Anything that requires decent STR. Aside from that, my low CHA will have me challenging monsters to arm wrestling duels who proceed to attack the party, and my 'circus' lore at +0 INT Bonus will be amusingly useless.
Now for my observations...
Sigrun: Your stunning fist overlaps with my combat bully mode. If I have an enemy prone, there's little reason for you to stun punch them down, as flat-footed doesn't stack and the other penalties require crits. Stunning Fist targets CON, however, while trip targets DEX. So we might prioritize who handles different targets based on their saves.
I in turn, however, will still prefer to lock down enemies if I can even if you have succeeded. In my role, in what aligns with other melee characters in our party, my way to help you is to make sure an enemy is penalized and can't move. Then we flank them and wreck them. Due to our sharing debuffs, however, we may choose to pair off with the other melee heroes in the party to better spread them around.
Yisake: My priority with you is to keep enemies away while you buff me or debuff enemies. All your spells will be pretty useful in a non-combat situation and you provide a few combat ones. In line with the above, your Daze spell puts flat footed on the enemies, which doesn't stack with a successful stunning fist or prone. Though in turn, my prone gives them a bonus vs ranged attacks. But your spell also targets the WIS save. So any very strong physical opponents with weak minds will be entirely up to you to debuff them. And You of course will be the only one the party trusts to talk to people.
Penda Alesiev: And to wrap things up quickly, you're currently our main damage dealer. All of us should be helping you achieve flanks and applying flat-footed so you can get in as many sneak attacks as possible. As pairs go, you might prefer Sigrun more than me, however. When I prone enemies, they get a bonus to ranged attacks, which requires you to approach in melee to gain your damage. And you will I think prefer to do safer ranged damage when possible, so Yisake and Sigruns ability to apply it leaves them standing as easier targets. Though if I can restrain an enemy, you can literally just walk up and stab them.