My feeling is that new rings will be better than the old ones, but if the next oversize pistons are available, I'd have the block bored (0.010" over if possible) and buy new pistons and rings.

If you are going to put in new valve seats I would replace all the valves and guides, and read Eric's advice on seals more carefully to understand the difference between the old and new seals.

I would be surprised if the valve springs were still within spec, but in any case, I would check them. You can rent or make a valve spring compressor with a C clamp and a piece of pipe with a window cut in it, and take the valves out of the head yourself. Label everything and keep the parts that ran together in a group.

Regrind the cam and have the lifters refaced. Worn lifters will wear out your new cam. Check the crank journals for out of round too. Replace every bearing, seal, and gasket that you disturb.

Rebuilding motors is fun, especially when it works out. The most likely way to have it work out is to inspect and recondition every part. It is not cheap, but done well it will be gratifying every time you start the car.

If you are on a strict budget, you can get by on the cheap, but it helps to know what corners you can cut. It sounds like you need rings and the cam and lifters reground at the very minimum ( I can't recall the details of your original post). If the valve seats are not pitted, you can lap the valves (as long as the edge is not sharp) and improve their sealing, etc...

Greg