Actually the immune system is one of the most vulnerable systems when it comes to inbreeding because it requires diversity of MHC genes.
Inbreeding and effects on the Immune System
How does Inbreeding effect the immune systems of animals
Inbreeding and the immune system: unintended consequences
However I totally get what you’re saying and acknowledge there may be traits that you want to keep in the collection beyond just the morph (maybe clutch size or something like that) and inbreeding may be the easiest way to keep that trait in your collection.
I don’t know anything about ASFS or their breeding so hopefully someone can jump in and answer this one