just in case that Random Ticket we get decides to trololo me and gets me a dupe of the girl I would have picked from the Coins exchange.
If you pick someone with RC, then you're not getting her dupe from that ticket
It's a no dupe unless you have every rainbow in the book, believe it's been mentioned like several times now

To bad the permanent 5K gacha is also random, since its only 2015 girls, they could have at least given you the option to choose.
2015 and 2016 ones are time-limited (they're 2 separate gachas)

Permanent 5k gacha is a ticket deal (not a random 6* deal)