"Also, central bank reserves don't circulate, so I'm not convinced "printing money" to accumulate foreign reserves to depress your exchange rate will "lead to inflation"."

I think you've got this backwards: the strategy would lead to increased reserve in foreign currency, but with more of the domestic currency on the open markets.
So, provided that those who exchange currency for DM are interested in spending them, it could lead to inflation/reduced deflation.

Especially if the quantities are huge.

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi