Are there different planes for Christ and Prophet Mohammed, and do these planes even exist? Where do the Hindu gods fit on these levels of planes? And above all, is it correct to understand that there is only one Supreme above them all🤨?

From the accounts provided of the Heaven of the Christians and the Paradise of the Muslims it seems more like the vital heavens, Swarglok of the Puranic Indra. Indian mysticism never saw it as a final nor the highest destination but a transitional resting place. There is much more that is beyond these heavens and paradise described in Sri Aurobindo’s Savitri, Book Two Canto 9. 

Of course there is the One Supreme Divine above all these manifestations but these religions don’t much believe in it. The Supreme Lord according to them seems to be an exclusive Power that brings benefit to the believers and punishment to the non-believers. Such an unjust and exclusive conception of the Divine is only possible at the Vital plane or at most the higher Mind. Even the gods of the Overmind understand that though they have each their own powerful domain where they exercise their total influence, yet there are other equally powerful domains with which they work in collaboration. But the Christian as well as the Muslim conception of the One God is quite exclusive, as well as hard and crystallized. So such a One Supreme is spoken of by different religions too but the meaning and conception of this One Supreme is very different from the conception of the All-encompassing, All-inhabiting, All-upholding One Supreme of the Sanatana Dharma. 

Affectionately,

Alok Da