The key is in their nickname (666line wrasse).
That rockwork isn’t going to be enough to suit their needs, you want Atleast a 3’ tank to have just enough rockwork for them to be happy.
A Clown goby is dead to a sixline unfortunately. And infact most peaceful fish will be dead to a six.
I had a sixline in a 3’x2’x2’ tank with a ton of rockwork (it left almost no room at the back for swimming), and he still killed a CBB with my old scopas tang. I really recommend skipping a sixline and going for a Pink Streak or maybe a smaller Halichoeres with the thought you’ll have to rehome it in the future.