IFRS - Comprehensive Income

For the fair value of assets, is the change in the fair value of all assets included in the statement of comprehensive income, or just assets that are held for sale?

All of 'em.

The change in fair value of AFS securities is included in OCI.

The change in fair value of trading securities is included in net income, which is included in comprehensive income (but not in OCI).

As a followup question, realized gains/losses on CF hedging, AFS, and trading securities are reported in the main section of the income statement?

Yes: all realized gains/losses from any source are shown on the income statement.