Forum:A couple of questions concerning Flip Summon

As the thread´s title says i have some questions about Flip Summoning.

1. There are some cards that say: "When this card is Flip Summoned (add effect)..." I have some problems. If that card was in face down defense pos and an opponent´s monster attacks it, Does my monster´s effect applies? Is there any difference between flipping face up and flip summon?

2. I just bought the Invincible Fortress Structure Deck and there are a few cards that have this (and others) effect(s): "Once per turn, in your main phase, you can flip this card into face-down Defense Position. etc..." Let´s say it´s my turn, i flip my defense position Guardian Sphinx into attack position (Flip Summon) it activates it´s effect returning all my opponent´s monsters (let´s say 3 Blues eyes white dragon). After that is where problems come: Am I still able to flip into def pos and face down my montser in my main phase 2? if I attack to my opponent´s life points directly, is it possible to flip face down my monster? or should i just wait till my next turn to do that?

3. This one is more specific. I have Golem Sentry, it can return an opponent´s monster to his hand when it is flip summoned, but in it´s lore it does not say the main phase part as in Guadian sphinx lore it just says "Once per turn you can flip this card into face-down Defense Position. etc..." Am i able to activate my golem´s effect in my opponent´s turn?