Interesting points. Unless the older Attack head was a Terry Bozzio series, it was NOT USA Dupont S-Mylar. That's the only USA material that they ever used. After the re-brand it was called Royal 1, which, as stated above, has been discontinued because Remo, whom they used to buy the film from, wouldn't sell it to them anymore.
I suppose it's possible that they are using the Remo factory in Taiwan, but unlikely. Here's why I think that:
1. If Remo was making heads for them anyway, why would they refuse to sell them the Dupont USA film? If Attack was using Remo's factory/materials, why would that be an issue? To me, it sounds like Remo doesn't want to provide product to a competitor trying to get a piece of their market share.
2. Following up on the last sentence above, Attack is an aftermarket drum head manufacturer/provider, and a completely different company than Remo (or anyone else). By default, this makes them a competitor to Remo. Why would Remo be helping a competitor manufacture products to sell in the same venues that they do, under their own (non-Remo) brand, especially at a price point that would be likely to take at least some of the market share away from Remo? Remo is such a large brand, you would think if they were making Attack heads, they would want them to read something like "Attack: Designed and made by Remo" or something like that. Plus, Remo doesn't sell their UT/UX/UC heads individually. Why would they be doing that for Attack (and let Attack make the money) but not themselves? Again, Attack is a completely independent company, no affiliation/ownership with Remo whatsoever.
It's an interesting theory, but just doesn't seem to make practical sense.