No. If you start the array like that, I'm pretty sure your cache pool data will be gone.
I believe the correct thing to do would be to set all cache devices to none, and start the array, then stop the array and assign both devices.
However, I'm not at all sure about it, so if I were in your shoes, I'd put it back like it was with a single device in cache2, and hopefully you can see your data, if so I'd follow the normal procedures to replace the cache disk by disabling the docker and VM services so they don't show up in the GUI, set all shares to cache yes and run the mover.
My best advice is to wait for @johnnie.black to chime in, he's much more familiar with BTRFS cache pool issues than I am.
WHATEVER YOU DO, don't start the array with that "All existing data..." message showing. It WILL erase your cache pool.
I stand corrected, thanks to johnnie.black. There have been so many threads with "OMG I JUST LOST MY DATA" when involving a cache pool I am overly paranoid that it's not going to work as advertised.