Can an upper eyelid surgical approach (to avoid visible scars on forhead) be used to decrease a horizontal forehead deep crease?

With difficulty. It is possible but difficult to do this through the upper lids. A more effective approach is endoscopically through small incisions hidden behind the hairline. Unless you are bald, that is the way to go.
Forehead wrinkles. The deep lines across your forehead can be addressed in a standard brow lift but not in the transblepahroplasty brow lift.
Yes. You need to see a specialist that does this, an oculoplastic surgeon.