Re: 11/15 Tiggy - reduced eating -dose/meds to watch?
If they give a probiotic for diarrhea (especially if it's a liquid or gel), there are some that contain sugar. Make sure you ask what are in the ingredients in any non-pill medication. Even some of the liquid antibiotics have a sugar syrup base. Many of us give FortiFlora for diarrhea, which you're already doing.
It really sounds like with the lip smacking that Tiggy is nauseated. I would talk to the vet about an anti-nausea/vomiting med. Many people here have used Cerenia (maropitant) or Zofran (ondansatron). Vets like to prescribe Reglan (metoclopramide) which is really for gastric motility issues and does little to address nausea (unless the problem is related to gastric motility). Pepsid (famotidine) may be an option but it doesn't sound like Tiggy has an acid stomach. If your vet wants to prescribe an appetitie stimulant (e.g., mirtazepine or cyproheptadine), if Tiggy is nauseous, it's important to get the nausea under control prior to starting an appetite stimulant. (Think about how you would feel about eating while nauseated.) All of these meds are fine to use with a diabetic cat.
Flagyl (metronidazole) is also used with GI issues if the vet thinks there's a bacterial problem in the gut.
With regard to dose, you're going to need to gauge whether you can get food into Tiggy. The balancing act is that if there's an infection brewing, food and insulin are important to keep ketones at bay. It's fine to shoot a reduced dose if you need to.
I want to really encourage you to get the vet to evaluate whether there's an infection. The diarrhea and loss of appetite started after Tiggy's surgery. It may be coincidence but it may not.