Ohh backstory from the real dogs (I want to see a dog who can fully express himself that way xD although our dog here may actually seem to be cheery too, his tail becomes a helicopter too when he approaches us so xD so let me rephrase that, I'd like to see a really huge dog be goofily happy although I'd probably lose energy first before his own dies. And I'd like to meet a Sparky too xD I'd probably be more comfortable with him since he'll probably be just lying beside me and waiting for pats if I feel like giving one.)
Although, I'm not new to renpy, I still feel new since I haven't really used it much to its potential (I just use the minimal and the stuff that I can understand without having to post a topic in lemmasoft, unless I really need to xD I'm amazed by your GUI though, are you using the legacy interface or is this the new one?). I wish I can help you with the random appearance of certain characters but I don't know any complex renpy or where the problem might come from so... but I'll be cheering you on and hope it gets fixed.
And YOU'RE WELCOME (x2)! I'm actually happy as well when I saw your comment on my VN and your VN intrigued me so I can't possibly not check it out ^^ (more points to Rex being a really happy dog).