Great things to consider. I plan on paying taxes on my Steem earnings as a form of royalty much like my royalties in self publishing. As far as the capital gains, that won't come into play until you sell, then it depends on if it is a short or long term capital gain. I would recommend anyone thinking of cashing out wait at least one year to lower the taxable rate from 50% to 20%.

For Steem, most of what I have earned has come since it has fallen below 1.00, so will overpay my earnings here and just average it out at 1.00 per Steem. Best to play it safe.