- "I attack the exact centre of the light source" doesn't work against invis + light source. A creature which has its Dex bonus to AC is moving around within its square to dodge attacks, and even one denied its Dex bonus to AC is still moving around unpredictably. In the particular case of Luminous Armour, it's hard to even argue it'd be downgraded to concealment (as is the case for an invisible creature underwater, whose exact outline is visible), because the light is so bright it gives people penalties to attack you in its own right and as such making out details is practically impossible.
- Greater Blink does not give you total control of when you are on which plane. You cannot, for instance, use it to stay on the Ethereal Plane and thus duplicate Etherealness (which makes you totally invisible, allows you to move through arbitrarily-thick Material Plane objects, and renders you invulnerable to attacks that do not extend onto the Ethereal).
- See Invisibility and True Seeing can see ethereal light sources. Otherwise, they are indeed invisible.
- Greater Blink doesn't give you the 50% miss chance from total concealment (and does not force opponents to guess where you are, as total concealment usually does). It gives you a 20% miss chance from etherealness, a 20% miss chance from concealment, and a 50% combined miss chance if both apply. Luminous Armour shouldn't negate concealment, so the miss chance from Greater Blink applies as it would without Luminous Armour (50% normally, 20% if they can see but not hit ethereal, 20% if they can hit but not see ethereal, 0% if they can both see and hit ethereal, 100% if you readied-action dodge an attack that can't hit ethereal).
- It would be nice if you mentioned what book things are from when asking a question about them. 3.5 has a lot of books, and it's tiresome to have to search through several of them.