I have fished the Esopus alot. It is a great river but primarily for smallish wild rainbows and stocked browns. It does fish very well in the fall as it has a pretty good isonychia hatch. Generally speaking it is more of a nymph river but fish will take dries and the fish are generally not selective as it doesn't get the hatches that other catskill rivers get. I have done very well on top during the fall iso hatch though.
Fish do run out of the reservoir but your odds of catching one are not very good, particularly in early October. There is always the chance though but I would not expect there to be many and wouldn't be what I would go up targeting.
If you aren't aware, alot of the flow comes from Schoharia reservoir out of "the portal". Release can be funny and they tend to do them around holiday weekends so it wouldn't surprise me if they do one for Columbus Day. The good news is that it could trigger some lake run fish to move in but could leave you dealing with high flows for a day or two.