If it's hot it is cellulitis , if it's not , it's edema. Secondary to a vein insufficiency
Probably edema, especially if it was an issue with the right side. Consider cellulitis, but chances are it’s edema, and could be presenting in other extremities
I think edema (it s not a diagnosis in my opinion, means too many things) due to cardiac disfunction should be bilateral and predominant in legs. You should do a more specific clinical examination, there is the need for more data. For now, could be everything (obviously there is edema)! also a gout attack or tofo