IALs do work in Crystal Report, but the user must be granted the IAL. If it’s an operational report (not quick report), then typically IFSPRINT must be granted access to the IALs, rather than the end user.
What sort of error message are you getting that makes it unable to work in the client? If it’s “unable to retrieve PDF file”, but that it works in the Crystal Report software itself when testing it, it’s very likely a permissions issue.
Creating custom views is possible but is actually not at all “recommended” by IFS, they prefer you use IALs. Custom Views can be created as modifications with Studio Developer. You can also create them directly through the PLSQL Backend if you have access to IFSAPP, but it’s recommended you follow the code generation of the views with all the required comments so that the view can be selected in permission sets to be granted.