2007 Subaru B9 Tribeca SUV with 226k miles, many lights on--5 codes when scanned

Note that the ECM stores previous codes, so that if engine idles without stumbling the misfires are historic, and probably related to wet ignition events. But that's the only good news. Check the coolant level, and then assuming you can get it to start and idle normally let it warm up and check for bubbles in the expansion tank upon static acceleration (have someone rev up if necessary). If you see evidence of this "percolation", AND you've overheated the motor several times, it's a likely bet that a teardown is required to replace the HGs. That you've also "seized" the motor could indicate that several problems, rendering the block weakened too. At 13 winters and nearing a quarter mil, I'd move on, as even if you swap in a used motor (which is your safest option), you've an old tranny and exhaust to worry about. I'm a fan of the latest OB/Leg 2.5i (2015.5-2019; disclaimer: I sell these), so would recommend one as a great move if budget allows. Good Luck. Ern TSG/B