There is no certainty what the missing consonants are at all.
There are over 3,500 possible combinations.
YHWH may or may not be a derivative of 'I am'.
We don't know and should we then just have a bit of a stab at it?
The evidence does not exist for Jehovah. It is a completely made-up name.
Now I don't care one way or the other, but it is always best to tell the truth. It is without the slightest doubt not the name of God. It is a constructed name from the 1300s that somebody in your religion liked and it had a good marketing ring about it.
There is not the slightest doubt that it is not the name of God. Please refer to whereu's post for accuracy.
