This is really a question would take a book to answer completly. I'll try to hit the main points.
Yes. What hops are added to does change aroma and flavor. Because of the blending of everything. (Balance of a beer)
Specifically alcohol with hop flavor and aroma interactions all have good aspects in wide ratios. Alcohol "heat" tends to make hops bite a little or apear spicy.
Hop Tea Will add bittering to the beer as some isomerization will happen if above 175°. Will also dilute the wort.
Hop extract. Is used for bittering and offers little for flavor and aroma.
When hops are dry hopped plays a huge role in aroma. To early and all those aromatics will be blown out with the cO2.
To make a tincture or hop addition with specific water/ethanol ratios. Would do little to improve a specific beer as they would all blend with the beer in the end.
I believe if a magic ratio of water/ethanol mix was discovered to extract all of a hops potential aroma and flavor. It would only do the extraction faster not more complete than a different ratio.