The tank is less then ideal, but is far from the worst thing in the world. The issue more then space, is going to be bioload. Strongly would recommend having filtration far on the "more then ample" side, rather then just having "adequate" filtration. Goldine's are pretty stocky, and more heavy bodied then most groupers, so even if they're not quite as long as some other groupers, they have a pretty large diet. As far as aggressiveness, they are definitely on the lower end of the scale. As long as they can't eat it, they usually won't bother other tankmates. Nothing like a Miniatus or Louti grouper. But as they get older and mature almost all groupers can be downright aggressive and mean, so something to keep an eye in the future.
Goldline Grouper, aka Goldenstriped Soapfish, is well, technically a Soapfish. Make sure you research on Soapfish, specifically their ability to release toxin into the water when stressed. While I've never heard of a case where a Soapfish did nuke the tank, they do in fact have the ability, so it is worth reading up on.