Shane, I was aware of your general dictate to avoid the Finder, but when I tried it with System Events, it was erroring on the getting the container, and it didn't when I targeted Finder, so I was just going for what worked (up to that point, ant any rate).
I was really trying to make the point Chris alluded to: manipulating a file path doesn't need *any* app. For a non-ASObjC example:
set vImagePath to vImageAlias as text
set saveTID to AppleScript's text item delimiters
set AppleScript's text item delimiters to {":"}
set vImageFullName to text item -1 of vImagePath
if (offset of "." in vImageFullName) > 0 then
set AppleScript's text item delimiters to {"."}
set vImagePath to text 1 thru text item -2 of vImagePath
end if
set AppleScript's text item delimiters to saveTID
set fileFound to false
repeat with anExt in vExtensionList
try
set theAlias to (vImagePath & anExt) as alias
set fileFound to true
exit repeat
end try
end repeat
if fileFound then
tell application "Adobe Photoshop CC 2015"
open theAlias as Camera RAW
activate
end tell
end if