Thanks to everyone here for the responses, they gave me a better perspective on the importance of some components.
I did end up going with most of my component choices from my initial post (the .1% resistors aren't that expensive and the C0G caps won't hurt anything) except for the non-polar caps as that would increase the number of items on the BOM while the original caps should be fine.
As for grounding the PCB, I did use a copper pour on all layers connected with plenty of vias. Early in the design process I did have plated mouting holes but in the end those got removed for fear of creating ground loops. Maybe I'll at those back if I ver do a rev 2 :p
For the community I've made my own JLI-2555BXZ3-GP saddle 3d model public so anyone can print it.
I'll attach some pictures of the finished result for closure on this topic ;)
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