Yes, they are included. But they only have molex plugs, no 3(4) pin fan plugs. So they are not adjustable.

Good evening 1-piece 1800w-2000w power supply

Depending on the slot width of the cards, there should be room for the following quantity: 2-slot: 8 pieces 2.5-2.7 slot: 6 pieces 3-slot: 4-5 Of course, an air gap of at least 2 cm is included everywhere, provided the cards are placed on risers. Otherwise it depends on what kind of cards are used (and of course space is needed for other components). Also pay attention to the length, with extremely overlong cards it could be tight (middle fans may have to be moved or dismantled).

No, a mainboard with standard format is required in this enclosure