I used fresh roasted whole beans in the keg with great success. I went with 6oz in a mesh hop bag and in about 36 hours the beer had a fantastic smooth coffee taste.
I would give it some more time. I recently used wlp099 on a 1147 Barleywine that stalled at 1050. It took a week or so to start but after it has knocked out a point about every 2 days. Last gravity sample was at 1042 and there is still airlock activity.
Just got a bmb with the new lid. It pops out by itself with little to no pressure. When I purchase something I don't expect to have to modify it to work properly. I will not be purchasing a second.
I have found that it behaves the same as any other saccharomyces strain. I've heard that it is capable of creating a pellicile but have not seen it. Have it fermenting in a pale ale now and it will probably be done in 7 days. I ferment at 72-75 and get more fruit esters from this strain than any...
IBUs might be a little high for the L. Brevis and 644 isn't actually a brett strain but it is great yeast.
5-10 IBU is what I shoot for when souring with lactobacillus.