What's your question? Ask

This article will explain how to do just this: https://www.gardeningknowhow.com/ornamental/foliage/yucca/separating-and-repotting-yucca-offshoot-pups.htm

These yucca plants seem to be suffering from a fungal infection. This can usually be remedied by adding dolomitic lime and wettable sulfur to the area around each plant that is affected. This will repair the soil to a more suitable condition.

This depends on the size container that it is is now. Can you include a photo or describe it?

Yucca plants, when established, can be one of those plants that are nearly impossible to get rid of because of the massive underground root system they form. Mow it down, it'll come back. Dig it up, it'll come back if you leave any bit of that root system still in the ground. In your case, it may be overcrowding and choking itself out and digging up part of it, or dividing it will probably help it to grow better. Where I live in WI, I've had that same variety of yucca in my yard and spent 3yrs trying to get rid of it. All my efforts of mowing it and digging it up only seemed to make it come back looking better each year, lol. In the end, the yucca won the battle.

Yes, it appears that it will survive. Just be very careful with the remaining roots, and care for it as you would normally.

Yes, they are quite adapted to being dry, and will recover just fine once planted. This article will help: https://www.gardeningknowhow.com/ornamental/foliage/yucca/caring-for-and-landscaping-with-yuccas-outdoors.htm