Is it considered polytheism (shirk) to supplicate to Ramadan so that it may bear witness or intercede for a Muslim, or to supplicate to the Prophet (peace be upon him) and ask him for intercession, knowing that neither of them will do so except with God's permission?

It is not permissible to seek intercession in this world from a deceased person or an absent one, such as the Prophet or the angels, because this has not been authorized and is considered a supplication to other than Allah. For this reason, the Companions did not do so after the Prophet's death. As for seeking supplication or intercession from the deceased, there is a difference of opinion whether it is polytheism or a means leading to it. However, directly asking the deceased to fulfill a need is, by consensus, major polytheism (shirk akbar).

Similarly, it is not permissible to say: "O Ramadan, intercede for me," because Ramadan is a month and does not intercede. Intercession is specific to fasting, and this is a form of seeking from other than Allah and an transgression in supplication. As for saying, "O Ramadan, bear witness for us," it is preferable to avoid it.