I would suggest that you go to HD website and select your local HD store in the upper left hand corner. Then place the order for it. If your store has it then they will notify you when order is ready for pickup. It will also show you number of pieces in stock at near by HD stores.
If Home Depot does not carry it, try other lumber yards. not a common size, I think. You also may inquire if Home Depot will special order it.
MCA - Micronized Copper Azole
These are rounded.
You will have to rip your own 2 inch wide strips from planks that are planed 2 inches thick. You can get close by stacking two such rips from nominal "5/4" deck planking which actually is a hair less than 1" thick. Also check out the dimensions of "brick mold" trim to see if you can come up with a usable combination of off-the-shelf items.
When they dry out, they will shrink to about 1-1/2"
Unfortunately I am unable to answer your question. Please call the local Home Depot store and talk to a sales associate in the lumber department.
1/8th max and always predrill with wood this narrow
Folks are not answering your question. You already know that a post-War "2x2" is normally 1.5 x 1.5. You want to know why there's an additional 1/4 inch missing from these 2x2s. I don't know for sure, but I suspect that a stick measuring a full 1.5 x 1.5 wouldn't fit in the routed sockets in those pre-drilled railing top and bottom pieces, indicating this practice is quite widespread and intentional for 2x2s which are most-commonly used for railings. Also these sticks have "rounded edges" which may allow a mill to take additional liberties with the overall dimensions -- perhaps simply to slice more sticks per board at the mill and make a higher profit, perhaps simply sloppy advertising.
No, they must dry out first. You will know they are dry when you can splash water on them and the wood absorbs it.