The wear pattern on the bearing shells looks nice, they should be good to go back in. The exhaust valve seems to have been leaking a fair amount, and the intake valve seat has black areas too, so they both need lapping. Remember, the most important objective when lapping is to ensure that no trace of lapping paste gets on the valve stem and finishes up in the valve guide: that would ruin it immediately, and cause a problem.
The balance shafts, and of course the camshaft, have to be timed correctly when you put them back in. There are timing marks on all three gears in the balance system (the one on the crankshaft, and the ones on the ends of the balance shafts). There should also be marks on both camshaft timing gears (one on the crankshaft and one on the camshaft gear). Don't feel certain there will be, though: I have a GXV120 that had no timing mark on the camshaft gear. Fortunately I checked before I dismantled it, and made my own mark.
Note that black smoke is not oil smoke, it is petrol smoke caused by rich mixture. The engine does seem to have been burning oil, though, by the look of the top of the cylinder in your pictures. When you take the piston rings off the piston, you can check the ring gaps to find out how worn they are. We can talk about that when you get that far.
I hope you have a productive week at work, and come back ready for more fun.
