I still got no news about the minting/sealing of character NFTs but it's highly possible in the future.
If we're following the earlier blockchain MMORPG's like Mir 4 for example I think the profitable months to sell an NFT would be within the first 2 months of the release.

Engineer and rogue are both great choices if you're a F2P player as you can get the core skills without cashing in.