Did you test this setup yet? Also, are you only planning to use the ASIC chips to compute one SHA256? Because according to this https://bitcoin.stackexchange.com/questions/84616/how-specific-are-asics-design-can-they-single-hash-sha256 the way they are designed let's them only take a "fragment" of a double hash as input so they are unsuitable for computing single hashes.

So there's a lot of SHA256d hardware scrap lying around in the world but you need to wire logic gates and circuit boards together to create an ASIC that's designed for RIPEMD160(SHA256) and another kind for HMACSHA512. Unfortunately I don't think the ASICs used in bitcoin miners can handle those computations (keeping in mind the word ASIC is a generic term for hardware with logic gates optimized to do one function).

But I'd love to see benchmarks of SHA256 on your FPGA vs. a CPU and GPU. And also those of SHA512 and their HMACs while you're at it.