Help.... working on slopes over 50% gradient.!!!

Hi.. I would appreciate any help or advice.

I am currently in Southern Ecuador introducing permaculture to families here. They live in the mountains and many work on lands over 50% slope.
Currently many of the families are only planting corn here so I want to introduce them to the three sisters...

However on the steep slopes there is a large problem with water retention and run off.
At first I wanted to introduce swales but have read that on steep slopes they are not a viable option.... We are a team of two working by hand so large scale works are not an option. (impossible for machinery to reach some of the land we are working with. )

Any help or suggestions would be appreciated....THANK YOU!

attached are some images to show...

    Swales are viable options on steep slopes. Just don’t make them bigger than maybe about a foot deep, but have many of them. The advantage you have here is that if stuff is arranged properly, you can let gravity do your work for you. For example, the Polynesians planted candleberry trees right next to the streams that flowed down the volcanic slopes into their villages, so they would drop the berries, which were used as fuel, into the stream.
    I suggest food forest (and just forest) to stabilize the slopes.
    Using three sisters is a good start, sunflowers and amaranth are reportedly good companion plants for all of the sisters, as well as being awesome chop-and-drop chicken feed and bird attractors. You can stabilize the corners and right, left and downhill sides of the garden beds with perennials.