You need to decide your goals before anyone can tell you what is a good build.
Crank/balancer, factory crank is just fine. Many may say go aftermarket or to avoid excessively turned factory cranks. In the ten hard years I've flogged my 406, never a failed bearing or crank. Oh yeah, my rod journals are 0.020" undersized too - so taboo. If you want cheap, do not internally balance (if you choose the right components, I question why to balance at all for these rpms). Avoid cheap aftermarket replacement harmonic balancers, they are junk! I have spun two Spectre balancers "apart" (outer shell turns on the inner shell). If you choose to buy an aftermarket crank and/or quality balancer, take the time to check the clearance (micrometer) before you fit it and hone the balancer to size as needed.
On the bottom end, most will say the stock 5.565" rod is junk so many will go with either a factory 5.7" (basically, any other non-400 large journal SBC factory rod) or an aftermarket 6.0" rod. If your goal is less than 5000 rpm, why bother? For sure, it will add extra expense and time to make you feel warm and fuzzy. When building my 406 the first time in 1996, I went with reconditioned 5.7" rods with ARP studs/nuts.
I didn't see anyone address it; once you switch from the stock to longer rods, cam-rod interference should be on the top of your mind. The cam lobes for cylinders 1, and especially 6, will likely be getting friendly with the sides of the top of your rod studs. You will need to grind the sides of the rod and top of the studs for clearance. As long as you're grinding those two, I suggest you match all the rest so the balance is still good.
I ran clearanced, factory 5.7" rods on my first build and it ran to 6000 rpm many times in the first four years of flogging at the drag strip and never failed so there is no question if it is reliable. However, it did not make me feel warm and fuzzy. When I pulled it apart to freshen the rings, I switched to Lunati Street Race rods which utilize a rod cap bolt instead of a stud. When assembling, I was fully expecting to need extra cam clearance for these rods too but was pleasantly surprised to find nearly enough clearance already. I say nearly, because I wanted to make sure if I switched cams, I would still have plenty so I just touched the tops of both sides of the rods with a grinder. These rods were cheap (at the time only $400), relatively light (610 grams, as an I-beam compared to H-beams) and my preference for an engine that was going to see occasional drag strip use to 7000 rpm.
Oil pump; a good stock replacement is fine - avoid high volume, no need. Again, if you want warm and fuzzy, add a high pressure spring if you want - it's cheap. Support the oil pump pickup with an arm that bolts on to the pump and welds on to the pick up.
Piston choice? How could anyone want to run anything but a hyper eutectic in a street or light strip application? Just remember to file fit your rings accordingly or you will be breaking the tops of the pistons off at the ring lands (******** not clearancing the rings correctly for these pistons is how they have gotten mixed reviews). I'm 100% in favor of file-fit rings when assembling engines with non-factory pistons. If you decided to go with 6.0" rods, the piston pin coincides with your oil ring - pay attention to the piston manufacturer's instructions for fitting the rings.
Compression, cam, heads, intake and carb - need to know more about what you ultimately want from your combination.
Cliffs - stick with stock rods and crank, it's cheap and easy if you're only building for 5000 rpm.