I don't know the answer to your question, but I do know Florastor contains just ONE strain of probiotic. The one strain is Saccharomyces boulardii, a probiotic yeast. Coincidentally, this strain is one and only strain Elaine Gottschall (of the SCD) identified as NOT beneficial for Crohn's folks.
That said, any probiotic has the potential to give a person extra gas for several days until the body adjusts--this is considered normal. Probably not extra mucous, though!
There are many, many brands of probiotics on the market nowadays. Many have 3 or more strains of beneficial bacteria. I don't think I have ever run across S. boulardii in ANY of the popular brands at the health food stores....