Regarding the irritability and fussiness, it is difficult to isolate the exact cause since your son has two problems: the acid reflux and the colics, both of which can cause irritability. Infantile colic are hypothesized to be caused, at least in part, because of an imbalance of the gut microbiome (the "good" bacteria that live in the gut and help ferment the food and produce vitamins), so probiotics may help by re-establishing this balance.

Here I would like to ask you if your son has gastro-esophageal reflux disease (GERD) or mere acid reflux? Because GERD requires investigative tests to be diagnosed and is more serious than simple infantile acid reflux which gets better on its own as the child grows.

So here's what I recommend you should do: if this frequency of bowel movement is was more than the baseline for your baby and he continues to be fussy, have him examined by hos pediatrician; it would also be a good idea to have a stool analysis and culture to make sure he does not have an infection, especially if you detect elevated temperature.