I have run an older Vulcan headlamp. The older Kawasaki Vulcan headlamps use the same bulb as the stock EX500 bulb, so no need to alter the wiring.
Far as mounting, there are plenty of different ways. When I mounted it on a gen1, I used some generic aftermarket universal headlamp mounts and then chopped and welded the instrument cluster mounts to the headlamp mount and called it a day. You can also try looking for the stock headlamp mounts off any older cruiser. Many utilized a tab coming off a tube which was sandwiched between the upper and lower triples, making it relatively universal. The advantage with using older OEM parts sourced from different models is the quality will be much higher than most universal aftermarket stuff, not to mentioned cheaper.
Mounting up either the original turn signals, older cruiser/naked turn signals or aftermarket universal stuff shouldn't be too hard. Be sure to get 3 wire signals if you want to keep the running light function. Also, you get what you pay far, beware of cheap-o Chinesium stuff off Amazon or Ebay.
1990 EX500 - 146,000 miles as of February 2nd, 2020
1993 Ducati 900SS - The real canyon carver