Your income for that year is your income. That is what the EFC is based upon. If you make less the following year, that will be reflected in your EFC for the next year.

You can make a note about why it was atypical...but it does not matter, since they are based upon one year, not some running average over time.

Yes, they count, which is why advisers recommend avoiding realizing in critical years, or at least harvesting losses (plenty of those at the moment).

Same as employment income for the year you sold the stocks. If you have lots of gain, best to try and wait to sell those stocks Spring of Junior year so it’s not counted in FA ( or Sophmore year of High school) - assuming you can time it.

Anyone know how financial aid works for capital gains? We liquidated some stocks for college tuition. There's a capital gain for the sale. Is this cap gain counted in the same category as salary for counting EFC? Or do one-time income items count differently than employment income?