I just picked up Brewie, and I plan to run him in 10T. (Gremlins are cute and all, but, you know. Dragons > Pigs.)
I haven't had a chance to play him yet – got to custom base 'em first – but I've been considering what my core crew will be.
Without Trixie, I think it's going to be critical to use some AP control. Yin looks like she'll do a lot of amazing things for Brewie – she can almost ensure that you'll lock down that important piece with Brewie, she screens him nicely, she's hard to kill and she adds another layer of disengaging shenanigans to his bubble – but she also gives tomes to Komainu. That means they'll be auto-spotting Slow triggers; with their (0) teleport and Ml 6 vs. Wp, they should be able to chew through quite a bit of enemy AP.
While I'm hesitant to list-build more than that – I'm already some 28ish points in after accounting for cache and upgrades – I'll likely need some Df-targeting damage output. (I don't like to skew too hard.) The Illuminated feel like a natural fit – fast, self-sufficient and killy – and Katanaka Snipers seem strong, too, and can help hand out Slow in a pinch. Oh, yeah, and Yu, I guess. (Is there any 10T list he doesn't fit in?)
For a different take, Chiaki also looks promising, but she brings a different set of demands to the table. I'd probably still take a single Komainu with her, but I'd look around for a diff't bodyguard than Yin; I'd want someone that could screen Brewie and Chiaki both. (Sidir seems like a decent choice. It's where my impulses lead, anyway, and he brings a strong Df-targeting attack – and likes to fire into Slow models.)