A big shout-out and "Thank you!" to @Tim S , @Wes W and @Daniel W, with special thanks to @WilliamReynolds , @Pedro I;Tellez Corella , @James D , @Julia T , and @Ulrich B for all your kind help and support. And of course special mention to Joan for her original work on the pigpio library and daemon (http://abyz.me.uk/rpi/pigpio/sif.html ).
After a solid week of staring at Python code, endless Googling, and seemingly endless trial and error, I was finally able to achieve the first steps toward achieving my goal of native Xojo control of remote Raspi GPIO function over Wi-Fi without an intermediate Python layer.
In answer to my original questions:
1) Einhugur's Python 3 script plug-in is fine work, but it uses Python (of course) and it does not address remote GPIO functionality.
2) Xojo's own GPIO module is also excellent work, but it too does not provide remote GPIO functionality.
In the end, I was able to communicate with the pigpio daemon remotely via TCPSocket natively in Xojo with surprisingly little code.
This code connects to the daemon:
TCPSocket1.Port = 8888
TCPSocket1.Address = "192.168.2.15"
This formats the socket message:
Function Pack(cmd, p1, p2, p3, ext)
Dim pad as string = chrb(0)+chrb(0)+chrb(0)
Dim cmdCode as string = chrb(cmd) + pad + chrb(p1) + pad + chrb(p2) + pad + chrb(p3) + pad + chrb(ext) + pad
if p3 = 0 then cmdCode = left(cmdCode,16)
And this sends the message to control the GPIO pin to turn on an LED:
Dim setmode as String = Pack(0,20,1,0,0)
Dim write as string = Pack(4,20,1,0,0)
Of course, my code is probably a bit sloppy since I am still very inexperienced, but it's simple and it works well.
Amazing! How is Xojo not at the top of the list of the most popular programming languages?!
I've marked this reply as the answer to my original question. I hope that is not breach of protocol or appears vain in any way. I just thought the question should be properly closed with a detailed answer for anyone else who might stumble upon the same issue.