Unless and until you have more information on the engine, I do not recommend running it vertical. Many accommodations have been made to allow it to run horizontal, many you may not see, and may not be standard otherwise. The lubrication system may not allow for vertical oil drainage, or some areas may not get oil, at all.

The oil "sump" is just the area engine oil collects after leaving operation. A dry sump allows for a much more compact configuration, as the oil is contained and pressure pumped from another location, eliminating the need for a large container immediately below the engine.

No, I do not suggest installing the oil filter in a suction condition.