You can drill and pin if you want to spend the money. The crack is not a death nell. You can run the motor for ever with that type of crack. Just use permatex on the bolt when installing the head. But I would do something to stop the crack form traveling further. It looks like a helicoil has been used.
The first pic is going to need to be cleaned up and fly cut for an oversized seat. The one of the bolt hole between the cylinders is a pretty common thing on these engines. Although they go into the water they don't always cause a problem. I would drill a small diameter hole at the edge of the cylinder. Thead it and insert a screw coated with Permatex High Tack gasket goo. Screw it in and peen it a bit, then grind it flush with the block. That will prevent the crack from going farther and into the cylinder. The same could be done with picture #1. Multiple brass screws should over lap 30 - 50%. A time consuming process but doable, and has been done forever. The hole with the recess around it may not seal with the head gasket. A bit of professional welding and grinding would fix the that part. See if the hole has an insert in it. If so, you may be okay with a good cleanup and threading any welds that encroach. It would be wise, if you have it welded to build it up flush with the surrounding area, to insert a threaded copper or brass rod into the bolt hole if you have any threads in the hole. The weld will not stick to it, and it would save some work. My biggest concern is pic #1. That is a huge mess and will take some expert machine work to straighten it out. Good blocks are getting so scarce now it might be worth the time and expense to save it. Good luck.
Oliver , FlatheadDave is right on the money ,,,,,,listen to him . I’m not certain about post #4,,,,,I think he might need a bigger computer screen,,,,,or a new pair of glasses . Tommy