What are all the ways to get these? I can't remember the last time I got one since VS rarely hand them out. And my most important question is Can they be used on Vincent??
Hello. You can get them from monthly packages on purchase (1 per month) or from Blitz rewards. It was also obtainable from the Green Manda Festival (Only hosted one time ever. 1k dark green manda = 1 ticket). I got the one in the photo below today. As for your last question, you can use them for the regular transcendance, but it's impossible to use them for Awakening (hence why people use their Transcendance tickets to finish the T3, then all regular copies for A3 Vinc)
Natara 
Muskrat
Hello. You can get them from monthly packages on purchase (1 per month) or from Blitz rewards. It was also obtainable from the Green Manda Festival (Only hosted one time ever. 1k dark green manda = 1 ticket). I got the one in the photo below today. As for your last question, you can use them for the regular transcendance, but it's impossible to use them for Awakening (hence why people use their Transcendance tickets to finish the T3, then all regular copies for A3 Vinc)