Pending P0016 code after head gasket replacement.

Have you seen this thread:

P0016 Error Code | PriusChat

Multiple possibilities, but something might catch your eye.

 

I think the crankshaft normally turns clockwise (as you face the pulley on end of crankshaft). This is from my recollection of how Gasket Masters break the pulley hold-down bolt loose by cranking the engine with a wrench on the bolt head. So:

If the timing chain is correct across the cam sprockets up top, but shifted counterclockwise by one tooth on the crankshaft sprocket, the valves will be opening and closing late??

 

First question has to be: you have a photo showing the yellow crank link one position off, but was that photo taken at the same time you visually confirmed the two camshaft links are on their respective marks?

Because the number of chain links probably isn't an exact multiple of the number of crank teeth, you'll be able to take photos showing the yellow crank link at various different positions on the crank sprocket. (If the number of links and the number of sprocket teeth are relatively prime, you'd be able to take photos showing the yellow link at every possible position of the crank sprocket.)

So the only photo that matters is one that shows where the yellow crank link is at the same time the two cam links are in their correct position and nothing has been touched.

Otherwise, just seeing the yellow crank link at the wrong spot on the crank sprocket at some random time doesn't tell you anything.

If it really is mispositioned when the cam links are on position, maybe by removing the tensioner and slipping it off the exhaust sprocket, you'd be able to dangle the chain enough to pull it back up against the crank in proper position? I've never tried it, but I'd probably give it a pretty determined try before resigning myself to taking the whole cover off again.