I've asked Inyo Management the same question about all the language implying that this program is mandatory. The reply I got was, "thank you for taking the time to point this out in our various publications."

The District Ranger confirmed there is no Forest Service Order. Almost every FSO requires a NEPA decision document to accompany it. Since they did not complete NEPA, they are stuck in an interesting dilemna.

Regarding the question about whether NEPA even needed to be completed for the WAG bag program. Well, Inyo certainly thought so since they produced a length Environmental Assessment with five alternatives. The WAG bag alternative had enough potential impacts to possibly require an EIS. Please read the EA and you'll see they were very worried about massive noncompliance and enviromental degradation. This is were a lawyer would have a field day for implementing something like that without completing NEPA for that alternative.

Regarding public comments: you are correct, there is no NEPA requirement to satisfy public opinion, it would be paralizing to get any project done if that were the case. HOWEVER, one of the main tenants of NEPA is to provide for public input into the decision making process. The decision document is supposed to decribe how public comments were considered in the final decision. It's in the NEPA guidlines and Forest Sevice policy documents. Here's a quote from the Forest Sevice template for completing the EA process:

Public Involvement
The proposal was listed in the Schedule of Proposed Actions on [insert dates]. The proposal was provided to the public and other agencies for comment during scoping [insert dates]. In addition, as part of the public involvement process, the agency [insert description of public involvement efforts and reference to documents in record detailing results].
Using the comments from the public, other agencies, and [insert others such as tribes, depending on the situation] (see Issues section), the interdisciplinary team developed a list of issues to address.

If removing the toilets and implementing a WAG bag program (Alternative 5) did not have impacts, then they should have simply completed a Finding of No Significant Impacts (FONSI) and a proper decision document including an explanation of how public comments were considered, and then they could issue a Forest Service Order. Instead, they were not transparent and Garry Oye published a psuedo-decision document implementing Alternative 5. He had the nerve to thank Whitney climbers for helping to find this solution.

EDIT: The need to properly consider public comments is especially important in this case because the solution shifts the burden for managing human waste from the agency on to the hiker's back. With public comments running 7:1 against this approach, and with the impacts described in the EA; it's seems arrogant to me to ignore the public, circumvent the NEPA process, and then pretend it's all above board and mandatory.

If this WAG bag alternative fails, these same people will be claiming that toilets won't work and they will call for reduced quotas, which seems to be the real agenda for some.