This is what i think: Dragon has guided Charlie to you cos he knows how you need to have an animal to love,and as for worrying about keeping him AND getting the pup! go for it! i once had 2 cats and a dog and they got on great-no fights or spit and hairs flying! i know you feel you are betraying Dragon, and i would feel the same, but remember--you may regret it if you don't, it will take a few weeks for them to settle down.
First i had Lassie, then Marmy came[my first cat] i was a bit worried at first haveing a cat and dog together, but in the end Marmy thought Lassie was his mum! they used to cuddle up together, then Tigger came, then Marmy had to be pts yrs later, so there was just Lassie and Tigger but he would'nt cuddle up with her, then Lassie passed away, then Meg came, and as you know, Tigger has now gone, so now there is just Meg.
anyway, i would think about it---don't you think it strange that this cat turns up out of the blue just as Dragon has passed on? sounds like an omen to me!!!!
Chris.