I waited until I had finished before commenting on this puzzle. I think it is absolutely fair although the rubric takes a while to master - though you can actually carry it out in steps. The clueing is very accurate.
I suppose the only issue is how you interpret the final comment about 'the rest of the grid'. However, any discussion about that is likely to reveal more than is appropriate, so I will say nothing about it.
A great construction, Gnomish - it must have taken a long time to compile.