Hi,
You have a lot of stuff figured out. I'll try to look at this in more detail tomorrow (Now midnight in Italy)...
Really need Igniter electrical characteristics. Is it anything like those used in smaller solid fuel engines? There must be good specs on this, unless you are DIYing the igniter in which case you will know or measure the resistance. Carefully.
Does "hybrid power " imply this is a combination solid/N2O fuel system? How far down might this be able to be throttled?
50+ years since I did serious rocket stuff, and that was CH3NO2 and electric arc ignition, fortunately by some test stand guys who knew what they were doing.
Go for the Flames 