When I remove the middle names to test FN/LN flow, [name]Elias[/name] [name]Ray[/name] is my favorite. [name]Flynn[/name] [name]Ray[/name] isn’t very natural sounding to me because they’re both one-syllable words. (I hear “a [name]Flynn[/name] [name]Ray[/name]”…as if it’s a product or something.) [name]Oliver[/name] [name]Ray[/name] blends too easily into one long word for me since [name]Oliver[/name] ends with an -r and [name]Ray[/name] starts with another. [name]Maxwell[/name] [name]Ray[/name] is okay, but the flow isn’t quite right to my ears.
[name]Oliver[/name] or [name]Maxwell[/name]… I love [name]Oliver[/name]! GL
I really love the idea of [name]Addison[/name] and [name]Flynn[/name] as siblings! I think [name]Flynn[/name] [name]Arthur[/name] is fab, although, I do think some of your other options sound better with the surname [name]Ray[/name]. [name]Flynn[/name] [name]Ray[/name] is a bit stunted, but I definitely still like it best. 
[name]Elias[/name] would be my second choice. [name]Addison[/name] and [name]Elias[/name]/[name]Addison[/name] and [name]Eli[/name] are lovely together, too.
Who would have thought such a simple last name would make things so difficult!! Lol