Hmmm. Not quite! Lol, sorry if it feels like I'm picking on you. I'm not, I swear.

Some answers needed here. How long has he been in isolation? He's 39, so that suggests it might have been some amount of time. He's old enough to have somewhat of a knowledge of the Exar Kun War (would have been a teen then, perhaps). 

Anyway, it's still unlikely he'd master four forms. He has age, experience, combat experience, so I'd say a certain level of expertise in two forms is definitely feasible. A crude knowledge of the other two forms you included is fine with me, after all; he's exiled and without a master to learn from. I'd say I recommend you have him be a master at one, and an expert at another. Intermediate or less at others. That many forms is just a lot, that's a lot of power especially because he's also expert at force push and pull. The combination of those and the numerous saber styles he has puts him on the level with high masters in the order!