Sounds like either timing or fuel. When I did the fuel leak mod I accidentally swapped the fuel line connectors ( stock routing is not intuitive ). It fired for one second then just chugged. I would guess it provides just enough fuel pressure to wet the plugs but not enough to run. Verify the hood sticker for proper hookup.
Some of my previous vehicles had fuel pressure sensors that would cut spark when too low. Might be why they light for the first revolution then stop?!? Not sure if Subie uses something like this.
Good luck, if the fuel lines or ground strap don't help I might re-check the timing belt alignment again.