1 - Reinfusing the previous runes would be fine! Methods that characters use in canon will typically work once they adapt to the magic of the setting (ex: wands and Latin-based phrases from Harry Potter, different foci, etc).

2- Also fine! Maybe don't make too many items filled with your own lifeforce, though...

3 - Higher levels of healing magic is fairly easy to access. Resurrection is far more difficult; very few of the natives are given access, much less those that come in through mirrors.