I'd suspect some bent valves because the pistons were freewheeling into the valves, which were fixed in place. You'll find out what the verdict is after the new belt has been installed. The bearings in one of the pulleys or the WP must have seized, so you'll need to replace that as well. Most of us who DIY this use the 4 piece kit and replace them all each time. Just position #1 to TDC compression, and align the marks.