We have avoided protein entirely for up to 30+ hr events. No need.
Homeostasis is a powerful thing. Consume adequate protein daily, and maybe a little more the day or two after and I’d wager that after 2-3 days (and probably only 1 day) there would have been no net muscle loss.
Certainly no need for protein consumption in anything under 12 hrs. Consuming 100-170g protein in the other 12 hours of the 24 available is no issue and will be sufficient.
Sure does sound like it. Their ingredients list is absent. I suspect there is something else in there. They also list 64g salt and 100g sodium citrate per 100g. I wouldn’t purchase this purely because it seems like poor quality control is extremely likely.
Sodium citrate is widely available as a cheese modifier or something. At least, that’s why amazon seems to think I buy so much of it. 
As I’ve shared elsewhere on this forum:
Using sodium citrate in place of table salt allows your gut to tolerate more sodium consumption during training. Sodium citrate has 3 sodium molecules for every 1 citrate molecule. Sodium chloride has 1 sodium molecule for every 1 chloride molecule. That means that for the same amount of sodium consumption, there will be a greater number of molecules ingested, if using table salt, rather than sodium citrate. Osmolarity is the number of molecules per unit volume of solution. Our gastrointestinal tracts are sensitive to very high osmolarity solutions. During normal daily living, consumption of very high osmolar solutions (lots of molecules per liter) causes a laxative effect 20-60 minutes after consumption. During exercise, it causes gut cramping, THEN a laxative effect. My personal experience with this can be described as “not fun!”