In short - no - you cannot technically build an interactive Mashup with Qlik Sense Cloud...yet. We are looking at enabling APIs to do such a thing, but this in preliminary discussion.
Building on what Bill mentioned - Qlik Sense Charts - allows you to create a URL of a chart object freely and embed it in a iframe, web-page - etc. - but there isn't any interactive capability - or wired chart capability.
Here is a quick video on the topic:
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