You do need to use the gate, log out and back in to get the reward gump and then use the gate again to use the reward (if your account isn't old enough I guess to use the reward you chose). However, my problem was that the same account on TC1 drops 5 months from what it is on LS. Therefore, it wasn't registering that I could get a reward so I had to try a different account. It too dropped 5 months from what it was on LS so I guess the account ages on TC1 are 5 months (thereabouts) behind from the regular shards.
Yes you do get to pick the cactus you want originally now, at least on TC1.