Not sure about #1, but in regards to #2 mobile data is rarely turned on.
As to #3, I found this on Brother's website:https://support.brother.com/g/b/faqend.a...000447_000. I was ignorant of Ad Hoc mode, which apparently is the "Brother_MFC_J430W" icon. The "MFCJ430W" icon is for Infrastructure. The printer's IP is set during the CLI configuration ("Will you specify the DeviceURI ?" For USB Users: Choose N(No) For Network Users: Choose Y(Yes) and DeviceURI number"). But more had to be done.
https://support.brother.com/g/b/faqend.a...100675_000 solved the issue. The "http://localhost:631/printers" Cups GUI appears to have been changed since the FAQ was written, but I found the correct place to select "http". All is well, thanks for the guidance!
As to #3, I found this on Brother's website:https://support.brother.com/g/b/faqend.a...000447_000. I was ignorant of Ad Hoc mode, which apparently is the "Brother_MFC_J430W" icon. The "MFCJ430W" icon is for Infrastructure. The printer's IP is set during the CLI configuration ("Will you specify the DeviceURI ?" For USB Users: Choose N(No) For Network Users: Choose Y(Yes) and DeviceURI number"). But more had to be done.
https://support.brother.com/g/b/faqend.a...100675_000 solved the issue. The "http://localhost:631/printers" Cups GUI appears to have been changed since the FAQ was written, but I found the correct place to select "http". All is well, thanks for the guidance!