I would suppose a guitarlele is really just a 17" to 19" scale nylon string travel guitar, tuned with the top four strings in uke tuning. To add to the confusion, octave guitars have around a 15" scale like a concert uke, and they are still guitars.
Do steel strings disqualify a short scale travel guitar from being a guitarLELE? Maybe, but if you want it to be a guitarlele, the line seems to be permeable, so why not?