The indirect toner I'm using could be any true toner (i.e. one that converts the silver grains formed in the first developer to a different metallic grain such as selenium, iron or silver-sulfide).
A dye toner (or tinter) does not actually convert the silver to a new metal; instead, the bleach (or mordant in this case) simply allows the dyes to bound to the grains which would otherwise have no affinity to them. Therefore, using a tinter would not be as viable since the silver grains that represent our positive image would still be susceptible to the blix. The resulting image, therefore, would be solely formed of the dyes which simply do not have enough density on there to be pictorially pleasant.
Your right though that the pH isn't an issue. That was never really an issue. In fact, I've already processed some 5,000 feet with the process using an acid-based BLIX. Here's a sample to give you an idea: http://vimeo.com/51802644.
However, despite how the process works, I wanted to see if I could go further with it and maintain the entire process at a specific alkalinity, which according to PE, isn't possible - or at least with the bleach agent at hand...