In WCMUsePojo class you can useSlingRepository repos =getSlingScriptHelper().getService(SlingRepository.class);to access SlingRepository API.You can increase the search speed by creating custom indexes. Also please check other classes in the bundle whether you are properly closing resourceResolver which you instantiated (In WCMUsePojo class you don't need to instantiate getResourceResolver( ) ).

You can create the structure using "infinity.json". For Example, if the page path is "/content/we-retail/ca/en/men" you can get the data from "/content/we-retail/ca/en/men.infinity.json" by using javascript(ajax call)

Please check your disk space

I believe you can do by providing the carousal properties as query string parameters to the Page B and manage Page B rendering based on query string parameters.