I'm here almost daily!
1 - I believe you could use it for any variation of a LUMEN RPG if you switched over the encounters. I use the specific ones for LIGHT. Feel free to edit the document as you see fit. I'll even publish an editable format today for you and update the license to be CC BY 4.
2 - A solo strike is 1 person by default. To play with more players in a strike, multiply the number of enemies by the number of players. This provides enough things for everyone to destroy during the strike.
Let me know if you have any additional questions.
- Cody