6: Your marked variation 1 is the most common move for white here, probably because it has a good relationship with the top right 4-3 point. If that is a 4-4 point, other moves become common.
Your variation 2 is also a fine idea but would normally start at G4. F4 is a little close, and probably allows black a strong pincer if he wants to. G4, K4 and K3 all follow this similar idea and are fine.
Of course, we must not forget that in the opening it is hard to find an actively bad move
8: This move is fine. Very good, even, as it sets up the kobayashi shape that is quite powerful. Black D18 is not worth worrying about, as it is quite small right now, especially since white is threatening a shimari.
10: Big area, but I think D5 is a better way to play. Black D5 would perfect his moyo, but if you play D5 now you live quite easily.
14: ...
A - Yes, I don't think this is a good point.
B - Very big. I think I prefer E though.
C,D - Big, but not urgent, I think. I want to prevent black perfecting his moyo.
E - This is the vital point of black's moyo. I think you should play it - if you think you'll get a weak group now, imagine how hard it will be later when black gets to go here!
It is annoying to let black play G17 or whatever later, so maybe it's okay to play there now, it is not my choice.
16: I still think D5 is a good place to enter the moyo. Possibly many of your ideas are also good.
20: I am inclined to make lighter shape, such as K6.
28: Maybe this is better at K2. This creates more interesting aji, thanks to the K5 cut.
35: I suggest a witty rejoinder, such as "so's your face"
36: Not worthless, but it's hard for me to say if it's better to play the L5 atari and M3 vital point - which probably gets at least 1 eye on the edge, though I haven't read if black has a strong resistance.
76: Yes, A is very big.
I'll stop here, since your main questions were about the opening, and the fight here probably dominates the game anyway.
