Glad you brought that up, there IS a difference between driver/passenger springs on the front. The difference isn't obvious, but one is longer to offset the weight of the gas tank (drivers side is longer). If you install them wrong, you'll have a bad lean. Unfortunately, I speak from experience here, I had to install mine twice to get it right.
XREAS is a closed system, there's no way to add fluid. What you read is partially right, once fluid is lost the whole system is trash. However, there are certain disconnect points, and as long as they are disconnected properly then there is no harm done to the XREAS system. The vehicle must be completely in the air with all four wheels bottomed out, then disconnect at the appropriate places. In the end, even though it can be done, I chose not to due to the risk involved.
You can rent a set of spring compressors for free at most automotive stores. You proceed with the install just as you would normally, and once the shock is free you leave the XREAS line attached. You can then proceed to do all the work there in the fenderwell. This makes you be a little more careful and is a little more time consuming, but very doable. Most shops I spoke with had bench mounted spring compressors and they couldn't do it this way. The ones I rented were portables that allowed me to work in the fenderwell. Most places I've seen that rent them have the portable sets (that's the only ones they had). Clear as mud?