RI - wheezing, bubbling from mouth area, "sneezing"
Scales - due to wet conditions, scale rot, or issues, get onto clean paper towels, or newsprint, check and clean often.
Mites - check for em'
General - get temps right, higher range may be better for RI, provide a hide for security. Your adopted may need more time than others before feeding, handling etc.

Sounds like a vet visit is planned (good on ya'). If possible bring fecal sample (poop), but get him checked out ASAP>