Thanks Brakke!
I think I should add it's not official Journeyman League. It's the local guys who bought starter boxes (six players). We are using the point progression system, but the schedule is not as fast and I'm not sure if we will play just the exact scenarios, and not using the same scoring system. Between us I think we have Cryx, Retribution, Cygnar, Khador, two or three Legions and my Circle (some are getting into more than one army).
I looked into Lanyssa just last night, and I think I just might pick her up as I like the mini and Hunter's Mark seems good.
edit. Gah Reeves are expensive! 50 euros for 10 small guys. I thought this game was supposed to be the cheap one when compared to GW stuff.
Sentry Stone & Mannikins though, I see two of them included very often and they would be a cheaper option money wise. Maybe leave Reeves to the later stages? Feels like I have to buy the deck too sooner or later and tokens so the cost does ramp up a bit.
Note that I haven't actually played CIrcle in MKIII so far, so this is theorymachine for me. This is moostly addressed at Tannith being your warlock as well.
You have to think about what you want your list to do, and also keep in mind what other people are likely to be adding to their battleboxes at this level.
Double Sentry Stones are great if you want to be able to somewhat safely deliver your army behind a forest wall, and possibly get a few boosted/aimed sprays here and there. It's more of a support pick, and means you'll be depending on the rest of your army to do the hitting once they get there. The good thing is that your enemies are very unlikely to have counters for it at this point. Also, I say double because this is one of those units that is much more effective when paired up.
Reeves(with or without UA?) are good all around. I can't remember how important the UA is to them in MKIII, but it's rare to take a unit without the UA. You'll be using these proactively to clear enemy infantry/support, and put some damage on heavies before finishing them with your own beasts. They're more versatile than Sentry Stones, but unlike Sentry Stones, they're probably easier to kill for some of your opponents. They do add a ranged threat that your army was probably lacking.
Skinwalkers are decent. Never take them without the UA. I'd only take them with someone who could improve their armor since they mostly seem useful for tying up enemies over multiple turns. I think Tannith and her buffs/debuffs favor units with more attacks though, so probably wouldn't use them with her.
Wolves of Orboros are decent too. I would take them before Skinwalkers, but after Reeves. They just die so easily. Not much else to say about them.
If you want to go a little bit outside the box, consider Farrow Brigands with UA as well. Assuming Tannith isn't super dependent on Friendly Faction for her buffs/debuffs, they would be comparable to Reeves. While Reeves want to shoot all day and hate getting engaged, the Brigands are actually solid in melee.
For solos, you have a lot of options.
Definitely consider something with Hunter's Mark. Lanyssa or a Blackclad. I actually can't remember their stats right now, but I would need a decent reason to take Lanyssa instead of a Blackclad, just because the spray seems like it would be better with Tannith.
Alten Ashley is just ridiculously good. He can be dropped into any list.
Druid Wilder is also nice for the free upkeep, but you have to be cautious of support bloat in Circle.
For beasts, I dunno. If high armor is a problem, you need Warpwolves to crack it. Satyrs can be good, but they struggle against an enemy that can really stack armor. I tend to think of Armor 19-20 as normal. Anything over that is stacked. I love Warpwolf Stalkers, and they're usually going to be the first beast I grab in a normal list. If I absolutely MUST crack armor, Ghetorix is next. For Satyrs, the Riphorn is the most killy one, while the Shadowhorn has the most tricks. I would buy the kit and magentize it, since I'm unlikely to run more than one Satyr in a list anyway.
Edit: Once you can start bringing extra Warlocks, a lot of things open up. Circle has always had a pretty deep roster of good Warlocks. I think Tannith, Kromac2, Wurmwood, Kreuger2, and Baldur2 are the top tier for us. In particular, Wurmwood seems very popular for tournaments. This all kinda depends on how seriously your group wants to take it though. I haven't been playing much, but our local group was fairly competetive, so most players treated game days like a tournament.
Either way, I do suggest you use the Steamroller scenarios ASAP.