Beautiful story idea! I think that there is a lot of potiental in this story that can be unlocked with character traits and backstories of their love.
As the Rudy is a raccoon who is slim-built physically, I think the character could have a number of emotionally and psychologically attractive traits: good sense of humor, intelligence, wit, friendliness, talent in creative subjects, and, of course, bravery in the face of distress, danger, and hard choices. That could serve as also driving the plot
I think the ref you posted was beautiful. As riverthekitty brought up, this is a work of fiction, so you could try a lot of different species/color combinations that also could contribute to her overall character. Just make sure you like her look. Personally I think ball pythons are very pretty
And for the question on how they met... I think you could do a lot with this. Rudy and Sarah's current jobs, friends, shared interests and personality traits could be taken into account for that big day/spiritual moment. Maybe they had similar jobs, she/he saved the other faithfully, Sarah had a disease he cured, or even something supernatural brought them together. Anyway, I think their strong bond as a couple could add to a theme of faith and togetherness through the piece