That all makes good sense (the SCSP worked quite similarly), and it makes the 45 MHz quote even stranger. That's double the core clock, and there is no way you could make even a cached ARM achieve that speed.
For playing DSFs, the important part is making the CPU as slow as possible without hurting the emulated program, so it works on a wide range of CPU speeds. It looks like that won't be a problem here since the ARM's effectively running slower than the GBA's.
As far as the rest, I don't know how much clearer I can make it that doing stuff from manuals is not an insult and doesn't mean you didn't put tons of hard work into your emulator. Nobody's accusing anything of being "ripped", and I could care less who discovered something first as long as the information gets shared. Posting info publically like this is certainly very welcome, especially for stuff that isn't open-source. Similarly the nullDC guys did use ElSemi's info, and they also credited him immediately without any prompting. It's all good.