somer is... one of the worst masters in the entire game now, (though gg3 is still kinda up in the air)
seamus core, high society and hats off should be good though, his keyword tends to lag behind seamus (1) himself so without anyone else in faction hes not as good as he could be, but is more than alright. however it is worth asking if anyone else in faction appears interesting for future expansion
if you arent aware, boxes like hats off are called title boxes, and the masters inside can be used instead of the version inside core, allowing multiple different crew strengths and playstyles. whether they're worth an early purchase depends on master (brewmaster for example *really* wants his) , seamus aint in much a rush but also stuff like mourners arent particularly useful so its still a good grab. the versions of the master are typically labeled 1 (core) and 2 (title)
also, not sure if its at all interesting but you can always try out faux online via vassal or TTS to see if those masters and/or keywords are somethin you wanna commit to, but so-as not to to hog this thread just dm me if that sounds interesting