1 ) Understandable. I often have issue writing other people's characters for fear of messing them up. I suppose with servants it's easier as, given the number of liberties that the main fate series takes with personalities, I feel a greater ability to shape them into something I like. There is technically the option to design something like a counterforce agent, though I admit I'm not 100% certain how summoning counterforce agents works. I am also working on some thoughts for how a master sheet would work, but for now that's a lower priority than working out combat. If you still want to try to use the character for the tests, I have further responses below and a thought of something that could be done with your abilities.
2 ) Ok, I suppose that's fair.
3 ) Ok then, though how much fire counts for each rank may be more of a judgement type thing than a hard and fast rule. Or, you could modify the skill to grant + mana per turn when in "Fiery Terrain"
4 ) Ok then, I'll leave it up to you to figure out what your + to endurance when resisting damage from fire attacks is, and you can add "You take no damage from fire terrain effects" to the effect.
5 ) Ok.
6 ) Ok, that seems good.
7 ) Ok, "In order to move through, move within, or exit the effected area, units must roll a successful Agility check"
8 ) Ok, and the pull in works with a contested strength roll. I had a possible idea that you could have the effect change the field to fiery and have you skill boost mana regen in a fiery field, in order to maybe have the Beacon of Flames skill work more like other skills in the bonds of the system.
Also, for everyone, I have a few people who have let me know they are working on sheets, and I am working on some stuff for school, so I'll start testing when I get the sheets in from those people and I'm done with those assignments.