Hey Thorgrim, first of all it depends on how strong you wish your list to be and what models you have and how strong of a list the opposition will be taking. But, as for viability in its current state against what I will assume to be a little above average lists taken by the opposition.
- If the OnG brings a doom diver or is generally shooty it will be a hard match up, else you're good as long as you play well.
- The Wood elf just has to hagbane the gyro and then kite you. Very hard to win against a good WE player with this list
- Skaven is pretty much the same as the OnG, it depends on if they have much shooting.
The Strength of this list is its Defense, With the oathstone flanks a flank won't be a huge deal, and the gyro will be useful to land a rear charge in such a small points game to make a difference.
But the weaknesses are it's vulnerability to shooting and magic. if The opponent takes any useful shooting they will have 3-4 turns of shooting before the slower dwarfs can reach the otherside, plus any magic spells. The Gyrocopter will play a huge role in making sure that you don't take too much damage crossing the board and getting a favorable combat. So your gyro should try to take out their shooting, then reduce the strength of their combat, and try not to engage in combat until you are sure you will be able to break atleast on of his units, which will be hard without greatweapons.
So it's not very viable but if it's what you got, Then "Ek an kazakit ha"