Cocoa asks why the café is named “Rabbit House”.
- “That’s because (the rabbit) Tippy is the shop’s mascot, isn’t it?”
Since Cocoa helps out at Chino’s house where she’s saying, she considers the situation if she were instead staying with Chiya.
Rize explains that Chino’s been acting cold because Cocoa finished off the puzzle Chino has been slowly working on.
Presuming or supposing something, with no particular information or evidence to back up that position, is expressed by appending だろう (from だ) or でしょう (from です) to a noun, verb, or adjective. As an expression, it has the meaning of “I wonder” or “don’t you agree?”