Finished modeling the two axis motors today and came up with a first pass at the motor to slide holder interface. It's not pretty but it should get the job done, assuming it isn't too much friction for the tiny Y-axis motor to handle. I'll print these 3 new parts along with the new focus motor mount Monday.
As far as electronics goes, currently I'm still using an Arduino running Grbl controlled directly by a PC (using serial terminal). Next step once I get everything working mechanically is to figure out the X/Y/Z steps/mm and speed/acceleration parameters to lock down in Grbl, then interface the Arduino with an ESP8266 running a basic web server for control.