The first item is covered, just the typical

/e/<noteid> url will load the thread for that note with proper threading formatting.

https://shipyard.pub/e/note1f724zaxtnuv77gxu2399ef78umlvqfjfnywfhrkkagyvunlz9peqt4e04y 

 Then how about /e/notexxx?reply=true to auto-open the reply form (with optional &text=xxx pre-filled)? 

 🤝🤝