In response to your final question, with modifiers, I would respond with a question for you to follow and decide for yourself.....
How full is the disk within your TimeCapsule?
Let us know what you find.....
Noting that the wireless access point of your TimeCapsule appears to be fully functional, and further noting that the installed firmware is updated to the latest useable version that your hardware supports, I would think that any TimeMachine issues with backing up are more than likely related to the condition of the disk.
