What supporting evidence is required for a Moroccan travel visa?

I plan to travel to Morocco later this year and wanted to check if anyone with previous experience getting a travel visa can shed some light here. The Embassy of Morocco in the UK states that for a travel visa, the following documents are required (among others):

• Copy of your detailed provisional flight itinerary.
• Hotel provisional reservation or notarized Letter of Invitation from your sponsor in Morocco.

However, Visa Guru...

Copy or Original hotel confirmation (Hotel confirmation must show paid in full.)

...and Visa HQ...

Copy of confirmed hotel reservations issued directly from the hotel.

...seem to imply stricter restrictions on what is an acceptable form of accommodation proof. So my questions are:

1. Is a booking done through a third-party site (Hostelworld, Expedia, the lot) acceptable?
2. Does the accommodation booking have to be paid for in full? (Because with some booking websites, only a deposit is taken.)
3. Is a hostel booking (rather than a hotel booking) - either paid partly or in full - even considered as a valid supporting document for a Moroccan travel visa?