Unfortunately I don't have the knowledge to comment on most of the features of your repointing plans, but I recently started working for a masonry restoration company and can offer some general repointing tips.
I hope they're useful.
When you're demoing out the old mortar, you want to cut it out twice as deep as the joint is wide. So say you have a 1/2" joint you want to go 1" deep.
You also want the edges where you stop demoing to be square, not feathered. This helps the mortar adhere properly. (Not really a big issue in a 100% repoint)
Ideally your mortar should be softer than the stone, so it wears away more quickly than the stone and can be replaced. You're on the right track by not using a lot of or any cement. You definitely want to avoid "specmix" and other really hard cement based mortar mixes.
Prewet the wall before applying the new mortar, as depending on the stone it may suck all the moisture out of the new mortar and prevent it from properly curing, especially a lime mortar that likely has a long cure time.
Good luck!
