McMourning box has nothing you can use in guild as long as you don't take a good doctor himself as a master, but he is fun to play. I see your start is similar to mine - I got Lady J and Sonnia, then bought a Lucius box... And so on, now the only boxes I lack are Hoffmann, Pale Rider and Ryle xd
Soo... I think that Lucius box is kinda weak. Personally I like the lawyers, even more as I mainly play against Neverborn, but to be honest they are not must have and as time goes on I tend to take other models. Guild guards - I could say that I like them but they don't make it to get into my lists often, they are very weak on offense and slow, tgough sometimes surprisingly resilient. Sometimes not And I find Dashel very lackluster, so I don't recommend it for you.
Hoffmann box is my next purchase, because I really like Hunters on paper and heard good things about them, same about watcher. So I would recommend this for you, I think hunters and watcher could work very nice with Sonnia. Can't speak about a Lady J, tried her twice this year and she is definitely not for me.. Her box though is very nice.