Okay, for a Pathfinder Society character, here is an odd combination, but it works. The "You killed Kenny!" build.
Assuming you have a high dex rogue with two levels so far.
Third level, add summoner. Just one level. Quadruped eidolon, Size: reduced to small;
Evolutions: Skilled Perception, Skilled Acrobatics, Improved Natural Armor.
Feat: Precise Strike.
That will make a 6HP/22AC flanking buddy that has an acrobatics of +15 to move into flank relatively easy without provoking AoOs.
It bites for 1d4+0+1d6 precise damage or does an Aid Another trying to hit AC 10 when it has a +4 to hit (0 STR, 2 flank, 1 size, 1 BAB). In other words, he should almost always acrobatics into flank and then Aid Another to aid your attack.
You end up with a flanking buddy that understands language, always obeys, is under your command, and that gives you a +2 or +4 to hit flanking advantage because it does the Aid Another with an 70% success rate. It will draw one attack that would have hurt you. It falls over after 6 HP of damage, but doesn't actually disappear unless the attacker does 17 HPs of damage and you are not willing to spend a free action to sacrifice HPs and keep it around. So, it falls over a lot, lays on the ground until it gets to -CON bleeding out slowly. But after the fight, you heal it some and it stands back up.
For your rogue/summoner, you take Precise Strike at 3rd level, gaining another 1d6 precision damage. That way, you are not behind a straight rogue while at third level. At even levels, you will be ahead of a straight rogue without that feat.
About 4th level, you should be able to afford a +2 weapon. Take a +1 Vicious weapon, and you will be doing +2d6 sneak, +1d6 Precise Strike, and +2d6 Vicious damage with a +4 to hit from your flanking buddy. If you are doing weapon +5d6 damage at fourth level, you are pretty effective.
Buy Infernal Healing wands with 2 PP as often as you need. Basically, you only need to survive through one battle, and then use the wand to get back to full HP for the both of you. The other wand you get is Mage Armor. Spam it as often as needed, and you will only end up using two Mage Armor wands over your career.
Skill points: 1 acrobatics gives the eidolon a +15 (1 rank, 8 skilled, 3 class, 3 dex), 1 Perception gives the eidolon a +12 (1 rank, 8 skilled, 3 class, 0 wis), 1 stealth gives a +11 (1 rank, 3 class, 4 size, 3 dex), 1 random pick. Chose the extra skills that become class skills as appropriate where you are going to spend these few points. The eidolon isn't going to be growing, so we optimize for the beginning. Having an extra party member with a high perception score is always a bonus. Since the eidolon can talk, it can convey all it sees to everyone, or can talk telepathically (silent) to the master across their link.
Shape: A small cat or small dog goes unnoticed when wandering around town. It is only going to have 1 bite attack because the evolution points are spent elsewhere. A serpent gets slightly better stats, but the slow 20' speed means it has less of a chance of getting to that flanking position. The 40' speed of the quadruped was one of the determining factors.
Or: If you go small bipedal, you spend one evolution point in Skilled(disable device) and you have a trap springer that never dies. He can only work on mechanical traps, but he really is disposable. If he dies, he comes back the next day. Since his STR went up 1, he has an 75% chance to pull off the Aid Another maneuver.
If Kenny does disappear for the day, you get CHA+3 speed bump summon monster I spells to toss around for the rest of the day. That is, if you have a CHA of 10 or better. I looked, and I don't see why a summoner couldn't have a 7 charisma. He would not get spells, but would still be able to get an eidolon.
The Rogue N/Summoner 1 is a very powerful dip combination.
Look at the Cloak of the Hedge Wizard and plan which you may desire to purchase later in your career. It may affect your choice of spells when you add the summoner level. In PFS, for a summoner, Mage Armor is a wand only spell. Don't spend your spells known on it. Good suggestions are Unseen Servant, Expeditious Retreat and Shield. Endure Elements is another wand that you buy once with PP and use it all through your career. While I am at it, Comprehend Languages is the other must have wand.
This combination works in PFS because:
1) five fights and you are done for the day. The fights are mostly spread out so you can heal between them.
b) 2 Prestige Points gets you a level 1 wand for effectively free. Grab a healing wand, mage armor, endure elements, and comp languages. After that, start stacking PP until you have 16 for the raise dead. Then start reinvesting the rest of the PP you make in more wands.
c) You never know what characters are going to show to a table. Expecting someone else to have a Cooperative feat is that helps you is foolish. With the eidolon, you ensure that every time.
d) You never get up to the higher levels where 'Kenny' just dies due to auras of the creatures you are facing. At the 9-11th levels, he will be a speed bump unless you are creative, but he was useful up to that point.
This strategy wouldn't work 'as well' in LPF, but still be reasonably effective. At least slightly above a straight rogue in my opinion.
As to the scenario you mentioned, [sblock=Spoiler]My greensting scorpion familiar was the one to open the door with a strength check. I had the DM just sputtering flabbergasted when I did it. [/sblock]