There is a mod for a Baofeng 888 too. That HT is about $20, You have to take it apart, solder in it, and void the warranty ASAP.
I keep seeing in these articles 2 radios. Do I need to use 2 or is that for redundancy? Am I reading it wrong?
If you want a full duplex AllStar node then you need two radios and a duplexer, just like with a repeater, or a full duplex crossband capable radio with tx and rx on different bands.
You do not need 2. But 2 only cost $24, So a spare is good, and you can use the second one to talk into your Allstar link. https://www.amazon.com/gp/product/B00ECW9DB4 You do need a programming cable, Because the radio has no keypad.
Full duplex is nice, If you can afford it. I can remote into my nodes using a computer, So a radio is not even required.
So if I go duplex. Then I will need two DMK-URI USBs and 2 sets of digi key parts correct to connect to one Pi3 box? I looked over the 888's but I like the idea of the others for location placement at my house.
No you do not need two DMK-URI USB adapters. 1 will control 2 radios just fine. The Pi3 will control 2 nodes too. It has a fast CPU.