So here's what I'm wanting:
Investigator with VMC cavalier with the order of the eastern star.
My intention is to use slashing grace or fencing grace along with challenge and studied combat to see my melee damage through.
This requires 3 feats, either way (weapon finesse, weapon focus, and grace).
I would also like to take Stalwart to stack up on the DR I'm getting from order of the eastern start, which would also require three feats (Diehard, Endurance, and Stalwart).
I will only get feats on 1, 5, 9, 13, 17. If I go human I can have enough to cover everything, no problem however very long term to get it done. However I think I would prefer combat expertise to fighting defensively, and eventually I would also like Improved stalwart if I can get the bonuses to make it worth while.
I would like to stay single class investigator.
So where I need advice:
1. Which would be better, combat expertise or fighting defensively, and what can I do to improve them?
2. Should I go with an agile weapon and skip the grace feats, use an agile weapon until later in the game and then get the grace feat or simply rush for grace early?
3. Should I consider any archetypes for the investigator? I was kind of looking at the psychic detective since it fits the theme with the order of the eastern star well.
4. Intelligence or Dexterity as primary? I'm thinking Dexterity.
If you can retrain and you're actually going to see those teen levels then retraining grace at some point is going to be a good idea. A +1 weapon ability will eventually be cheaper than 2 feats. Early on though it's too expensive even to use, then it's a significant cost, only later does it become a minor cost.
Psychic casting would be more useful if you didn't have a hand free anyway. Also psychic detective conflicts with empiricist which would generally be my first pick for an investigator. Further it prevents you getting a mutagen, and you were aiming for dex to damage. I wouldn't get it for this character.