I feel like I am asking a lot of questions on here since getting my cats and now I have another one 
We rescued our 9mo cat (dcat) about 2 months ago. She is a fussy madam and we finally settled on Applaws tins and Iams kitten dry which she was eating well, and producing normal looking cat poo. She refused several other foods, the only other wet food she would eat was Hilife if we mixed it with the Applaws but she started vomiting so we stopped giving it and went back to Applaws and this settled.
3 weeks ago we introduced dkitten into the house (I had wanted 2 all along). Dkitten arrived on James Wellbeloved kitten. They constantly eat each other’s food so when the Iams dry ran out I carried on with the JWB and bought Applaws and Cosma wet kitten food for the kitten.
For the past week or so dcat’s poos are much softer. Not what I would call diarrhoea but not formed, more of a blob with some form at the start or end. Dkitten is more variable - sometimes formed, sometimes more sticky. Dcat occasionally coughs up a furball, no more full on vomits since I stopped giving Hilife. Both appear well otherwise with lovely shiny coats. Both have recently been wormed. Neither are looking skinny. I have slowly stopped the JWB and moved onto Ava dry to rule out a reaction to the JWB. Today was the first day of just Ava.
Is this worth a vet trip for one/both cats?
Thank you!