Chlorhydroquinone is what is known as an "orphan" chemical which means it has no commercial uses. This accounts for its high cost and lack of sources. Each developing agent has a set of unique characteristics. Among these characteristics are redux potential and bromide potential. Despite its name chlorhydroquinone behaved more like metol than hydroquinone. So it could be used as the only developing agent. But there is no substitute for this developing agent. Ethol UFG used this developing agent and was later reformulted when it was no longer available. The results were not the same as the older version.
Champlin's book "On Fine Grain" is unintentionally funny but not really a source of useful information. Champlin was a commercial photographer with absolutely no knowledge of photographic chemistry. Dr Edmund Lowe, who forrmulated the Edwal developers, described it as "a children's story, where the evil dragon Grain is tracked to its lair and smothered with clouds of nickel ammonium sulfate." If you are looking for useful defveloper formulas then you must look somewhere else.