Sending vibes I hope Raven is well!!
I use pea flakes and oats for mine and haven't noticed them directly effect her gut. I only started in March as she would eat her Loxicom if it was in a teaspoon of oats and it avoided stressing her out by syringe feeding it. I sprinkle pea flakes in her hay, although she can't eat much hay, I like her being able to forage for something through the hay.
I second the Emeraid, I was feeding Excel dual care and she was maintaining weight for a few weeks, after I switched to Emeraid Sustain she's started to gain weight slowly (granted I do feed more mls but less often than I did the Excel). After researching, the Emeraid Sustain seems to be more calorific than the intensive care formula and helps build muscle. I found the 100g bag runs out really quickly so would aim for the 400g or even 2kg if you can.