Sure you can go with your sample of 2. But mathematically speaking with the stated URE rate there is a 33% chance of surviving the first 2 rebuilds. Far from impossible, but by no means an indication that your array is more safe than what the numbers suggest.
I wouldn’t worry about the STORJ data too much. Yeah, it’d suck to be disqualified, but you can start a new node and the data is redundant on the network anyway. But you seem to be using this array for other stuff as well. Make sure you have reliable backups for all of that.