kamikilla
You listing looks OK. You have covered all the key elements that the ECO needs.
To me, it does not appear that the ECO is considering a refusal. Just needs additional evidence of your intention to get married within the visa duration.
Whatever is driving the requirement for this we just don't know, could be anything, or could even be the manager.
Just as long as you can satisfy the request it should be OK.
As I said before the ECO knows very well you cannot provide firm bookings until your visa is granted, but just tentative plans.
Don't panic, just provide the info you can.
