Anfang pn. “Longbeard”

Question on the forming of Anfang. Coming from and and long. From what I can tell doesn't fang come from sɸaŋga? So it should be andasɸaŋga correct? Which would change the forming of the initial name. Unless they applied initial [s] vanished before spirants to it, but when you combine them it wouldn't be initial anymore correct?

I only ask because I am building a spreadsheet that shows how the compound words form. I don't know if anyone would find this useful but it is something I find interesting. [1drv.ms]

Yes, fang "beard" comes from ✶spangā.

The number of attested compounds in which the second element comes from a primitive form starting with ✶s-, and in which the normal medial developments are observed, are exceedingly rare. Instead, the vast majority of such compounds seem to have been formed later, once the [s] has already been dropped (rule S3).

Though we do have a couple of examples that seem to be older formations. One that comes to mind is (N.) gwastar < √STAR. When it comes to ✶sp- forms, I can only find one example where this cluster is allowed to develope medially: esbin, from ✶ṣpini; here the initial [s] is syllabic, and we observe the following development:

✶ṣpini > espini > espin > esbin.

But that doesn't really help us too much. We might speculate that ✶andā·spangā would develop into anbang, but we have no further evidence to support this hypothesis. Either way, it seems that anfang is a later compound.

Good luck with the spreadsheet! I'm happy to see such diligence!