I think the diagram should look more like this.
1. Penellii pollen goes to habrochaites not vice versa. I suspect this has implications for crosses as well.
2. The Arcanum I obtained from TGRC should set some seeds on domestic but not be a good bridge I have a second generation planted. That is ok, it looks useful in its own right.
3. The SC Peruvianum you (Andrew) obtained should set seeds on domestic. Probably won't act as a bridge, but that is useful in its own right.
4. We never had real Cornelio-muelleri and decided it was peruvianum.
5. The seed for Chilense I obtained from TGRC should be a decent bridge- if we could grow it to maturity (this year I didn't plant it, last year no plant made it to blooming). Though the lone putative Chilense I obtained and grew to maturity from Sacred Succulents did not accept pollen from Peruvianum or Arcanum.