Unfortunately a tracking (or view) key only shows incoming transactions, so it's not super useful. The premine wallets only have 1-2 incoming TXs.
I've inquired with our security lead (Vlad) to determine a smart and secure way to demonstrate that these funds are intact. I'll follow up after I hear from him.
Also, forgot to mention above, the pool was updated yesterday:
The pool software was upgraded and improved to be better, faster and stronger, which means more blocks! Thanks for your continued support and patience. Issues with disconnects and timeouts should be resolved. Fee reduced to 1.75%.
We're in the process of devising a serverless approach to accommodate the new rebase software for a PPLNS pool.