Check out Holistics.io (disclaimer: I'm a cofounder). While I can't say we can solve all your listed problems above, we provide enough tooling on top of your DW to help you pre-process (clean, aggregate) them.

https://www.holistics.io/data-preparation/

And on the part about firehose data, you might already know this, but Kafka and their line of work should be aligned with what you're after.