Log doesn't seem particularly big. I don't think you can ever tell if a mediocre poop came from a big bear or a small bear. At least with any certainty. If I see tiny ones I think cubs and if I see ones with the width getting close to the size of a can, I can't help but start to think it came from a big guy. I wouldn't put too much thought into it. The main thing is you're seeing a lot of them and there will be lots more you're not seeing.
Saplings broken off at 6 feet could be big or small. Bears will pull them down, straddle them and rough them up in all sorts of ways. The part that would be the most telling is the part that is broken. If it's a small healthy tree and the part broken off is thick, you know it took some power. Anyway, you at least know the bear has the stones to be openly advertising his intent to service the ladies at a rough bar.
As for the color of the hair as mentioned they will straddle and rub themselves all over these. The hair is probably going to be either from the face or more likely the underside. A lot of blackies rock white or blonde patches / crests on their chest. Could be any color of bear.
If there are blueberries there in the fall, sounds like a good place to hit in the fall. What matters now is if there's good feed now. If there's decent grass, clover, dandelions, bug infested stumps/lots they'll be hanging out. With the freshly broken off saplings, I think they'll be hanging around.
Oh and if you spook a bear, mind the wind. Pretend to leave in whatever direction the wind was more favorable. You can wait for it to come back out (best if the bear didn't have purpose like feeding and just wanted to cross the road / trail) or you can actually leave for a bit (15-20 mins) and walk back in (might be better if you think he wants to hang out and feed).