Can I use some seleant on the bolt threads to keep the oil from seeping back through? Are those tty bolts?
One other question… the orange nipple in the pcv corrugated hose isn’t visible? Does this need to be replaced ?
The intake needs to be replaced or a fix kit installed if the check valve is gone.
You could try using sealant if you want too. Personally I would recommend replacing the timing cover gasket. Those bolts pass through the timing cover into the block. I'd be concerned that the sealant on the bolts would get into the timing chain.