When many photography courses require a "fully manual' film camera, that can mean one of two different things:
- A film camera capable of being operated manually, even if the camera can also be used in automatic or semi-automatic modes.
- A film camera that can only be operated manually and has no capability of using automatic or semi-automatic modes.
Although anecdotal, my personal experience has been that the latter is more often the case than the former. Instructors typically require this because it is impossible to tell from the images captured if a film camera was used in fully manual operation or if one of the automatic modes were used to produced the photographs a student submits for an assignment.
You need to check with the art camp for a clarification on this point. All of the cameras you have listed in the question would meet the conditions of the first option above but four of the six you list would not meet the requirements of the second.
When buying any older film camera you should verify that it operates correctly and doesn't have any light leaks that could fog loaded film. You need to include time to do this no matter which camera you wind up buying. It just goes with the territory of buying used film cameras.
The Canon AE-1 and AE-1P, Minolta X-700, and Ricoh KR-10 offer at least some automatic exposure control. The FD mount lenses used by the Canon AE-1/AE-1P are still reasonably plentiful and easy to find on the used market. The Minolta 'M" mount lenses used by the X-700 are also fairly common. The Ricoh KR-10 uses the same 'K' mount lenses the Pentax K1000 does and they are very easy to find.
The AE-1/AE-1P are powered by either a single 6V 4SR44 battery (various manufacturers have different numbers for it) or by 4 1.5V LR44 batteries. The LR44 button cells are still fairly common and major retailers sell them as they are used in a wide variety of devices from meat thermometers to wristwatches. The single 6V varieties are mostly carried only by specialty camera stores but are fairly easy to find online. Without batteries the AE-1/AE-1P are not operable. The horizontal cloth shutter curtains of the AE-1/AE-1P have not aged as well as the vertical travel metal shutters found on other cameras. The AE-1/AE-1P also have a reputation for a higher rate of electronic gremlins compared to other designs from the same era. Of note is that the AE-1/AE-1P offered shutter priority auto-exposure but not aperture priority AE at a time when most AE cameras were the opposite - they offered aperture priority but not shutter priority. The only way to manually select the aperture with an AE-1/AE-1P is to use manual exposure mode.
Without two LR44 batteries the X-700 can not take a photo due to the electronically controlled cloth shutter. The X-700/500/300 series of Minolta cameras were manufactured in a very budget conscious manner and most examples haven't held up as well over time as some of the others you have listed.
Two LR44 batteries are required for the KR-10 to be operable. The vertical travel shutter with metal curtains found in the KR-10 tend to be more durable than the horizontal cloth shutter curtains found in other models.
The Canon FT QL and Pentax K 1000 are both manual exposure only cameras. You'll likely find lenses for the Pentax 'K' mount far more easily than for the Canon FT mount.
The Canon FT QL uses the short lived FT lens mount and finding additional lenses for it may be difficult. It was the first Canon camera that offered through the lens light metering, but the meter isn't very sensitive and doesn't work very well in dim lighting conditions. There was an optional 'Meter Booster' unit that was the size of a small flash and attached to the camera's hot shoe that improved the meter's performance in low light. The 1.3V M20/#625 batteries needed by the FT QL are only available from specialty stores that stock rare battery types used by older cameras.
The Pentax K1000 is considered by many to be the archetypal "student" camera. I've actually seen a few course silybi back in the 1990s where the K1000 was one of a very short list or even the only acceptable camera for the course. The examples made in Japan or Hong Kong between 1976 and 1990 are all metal. The ones made in China between 1990-97 have a plastic lid and bottom plate. All versions have a rubberized cloth horizontal shutter. The LR44 batteries required to operate the K1000's light meter are still readily available at major retail outlets. Without a battery everything except the light meter still works and photos can still be taken at every available aperture and shutter time setting. 'K' mount lenses are also very plentiful on the used market.
From the above it should be clear that availability of batteries and lenses that fit a particular camera, along with shutter durability, are things that should figure high on the list when buying an older used film camera.
If she's allowed to have some auto-exposure capability I'd put the KR-10 at the top of the list. You can get batteries for it at Walmart and used K-mount lenses are plentiful and affordable. If she must have a manual only camera the K1000 is hard to argue against.