Ramos' crew comes in at 38 soulstones (if you make one set of Arachnids into a Swarm). The Latigo Posse will run 32 stones for the models included. You could take both as 40 soulstone teams and have some room for upgrades (though Ramos will be in a tighter spot).
Sonnia would be quite cheaper, coming in at only 27 stones, so she'd feel a little shorthanded there. Nicodem isn't a good choice when you first start unless you plan to proxy a lot of models as he is a summoner and can take pretty much anything Resurrectionists have.
I'd say Latigo Posse might be your best bet then. Both are pretty shooting crews, all the Latigo are armed and Ramos is support master though his crew can get stuck in it. Should give good learning opportunities to new players. I recommend switching crews each time you play, let's you shift your perspectives of how to use a crew, and remember to have a fair amount of terrain with a variety of traits to give both teams good options for approach.