That sounds good. My approach was simplistic.
For example app_db is problematic on nanobsd, as it cannot be saved on a read-only filesystem. Iax is a good thing, but rarely used nowdays, as it's not properly route-able protocol. timing_pthread - I'll have to look at this, but I remember having dependency problems on pfSense install. Disabling non-used modules saves memory too.
I'm using it flawlessly with 2 SIP phones and 4 SIP registrar accounts like this and never had any sound or whatever problems so far.
Has specific recommendations for working properly on pfSense. Plus the original sip.conf is huge and over commented, not speaking that each .conf file is installed twice - keeping only one fully commented is more than enough.
But having a full-blown asterisk-GUI indeed implies to solve all the dependency problems properly - and after all, renders the simple status GUI useless, as all the functions I wrote I suppose, are present in the big GUI.
I'd love that too - but requires lots of work, I guess...