De-fusion

So.. if I chain de-fusion to dark hole for bring stratos to field

Do stratos really miss the timing ?

(Well even stratos got bottomless-ed, he still search, right ?)

And another question : can I use de-fusion on my facedown monster ? since it was face-down by booked of moon, both sides already known its a fusion monster. And polymerization / contact fusion can perform both with facedown monster, (unlike contact with cyber dragon you cann't use opp facedown monster)

1.
Chain Link 1: Dark Hole
Chain Link 2: De-Fusion
============================
Chain Link 2: De-Fusion resolves (Stratos summoned)
Chain Link 1: Dark Hole resolves

Stratos summoned is not the last thing that happened, therefore, it will miss the timing

2. Face-downs are never public knowledge.

So... what happen if I defusion an absolute zero (ocean + stratos) without any chain

1. Use de-fusion
2. Zero return to extra

Will stratos miss the timing too ?

No, this time Stratos won't miss the timing because:
De-fusion Zero
De-fusion resolved, Zero back to Extra, Stratos and Ocean are summoned.
Zero leaves the field, activates effect, start a chain, he is chain link 1.
Stratos is summoned, you get the option to activate its effect or not, if activates, it will be chain link 2 in the chain Zero starts.
Zero is chain link 1 because he is mandatory, that's all.