I think cats are the most spiritually aware creatures on the planet and being a spiritualiset I believe we are surrounded by those that have passed all the time. My Dad (who has passed) recently played the tricks he used to when he first passed over, I've been a bit down lately and I think he was just letting me know that he and my angels are all there for me, I just have to ask.
I'm lucky, I have yet to have one of my own cats pass but it wont be too long. Dizzy, my furbabe who is in retirement with my Mum is 14, she will go sometime, hopefully a long time yet but I know when she does she will be with my Dad, visiting and looking after me.
If it gives you comfort to believe in the bridge and signs from those who have passed then who is anyone to judge