Does running an inline fuel pump on stock FPR and stock intank fuel pump
ruin FPRs or intank fuel pumps?

 

In theory, it shouldnt, but i think it does...
The stock fpr should limit the amount of flow to the factory setting, however, its setting was designed for the stock fuel pump and its flow rate. Ao after you increase the preassure to it, it will keep the same ratio of fuel compared to stock, it just might be increased.

But I'd double check this...