Hi Darvish and Ute:
Sorry I am coming in a little late on this one. Great questions.
It turns out
maha mudra is covered in the AYP book in the addition to lesson #71 on Asanas. It is in with the "sitting head to knee" postures as a more advanced version. It is mentioned in lesson #183 too, as well as in the glossary of Sanskrit terms both in the AYP book and online.
But you are right, Ute, it is not a regular part of AYP, mainly because all of its elements are covered in other parts of the AYP practices -- forward stretch, siddhasana, kumbhaka (breath retention), mudras and bandhas. etc. Even so, maha mudra can be used in asanas before sitting practices, if desired. Just keep self-pacing in mind for maha mudra in relation to all the other similar practices we are doing, so as not to be "doubling up" on kumbhaka effects.
Maha bandha is doing kumbhaka in siddhasana with mudras and bandhas, which advanced AYP practitioners do all over the place in sitting practices -- spinal breathing (yes, slow breathing has a kumbhaka-like effect), yoni mudra kumbhaka, chin pump, etc. These practices are variations on the same elements, with a different focus in each one.
Maha vedha is essentially maha bandha while dropping the body on the sitting surface from a few inches up with the hands. This is not an AYP practice, however it will happen automatically in samyama at a certain stage when doing the "akasha - lightness of air" sutra. In this particular manifestation it has been called "hopping." It is maha vedha occurring as an automatic yoga in samyama.
When we are doing the core practices of deep meditation and spinal breathing, the nervous system will know what it needs via the connectedness of yoga!
Also, see
Victor's topic on doing kechari, kumbhaka and other things during asanas, which has some valuable related insights.
The guru is in you.