Sorry for my late answer, I didn't have much free time during the last period.
1. This is not the problem of Aero Glass - it cannot influcence if some application draws something into titlebar with its own colour.
2. This will probably be the bug. The Win10 defaultly uses the caption color as blending the active color with the accent color. Thus if you set your own caption color then it may look wrong. I'm not sure what the correct solution should be.
3. Unfortunately, this cannot be fixed. In pre-Win10, window frame has been drawn as one big rectangle. Now, the upper caption is rendered independently and thus blur effect will be always wrong on the areas where it is connected to the rest of the frame.
4. yeah, this is bug.