Since my favorite I/O Expander MCP23016 is obsolete, I was moving on to the MCP23017. Aaaaaaaand then I noticed they have a bug , and Microchip is leaving it as a feature. The last pin on both ports is output only, and my 1st circuit is all INPUT, bringing me down to 14 I/Os only.

So I'm moving over to the MCP23S17 and SPI communication. Looks like I'm going to be playing with Gadelhas' code after all.