Does anyone think these two will appear in this new busou shinki anime? (not the moon angel one.) I would love to see there origin story. Arent these two alter egos of strarf and arnval or something?

Tempesta and Lavina are limited edition, alt versions of the stock versions in the Shinki universe. It's possible them may show up. It'd save on VA costs in any case. But I suspect if they havent shown up in the OP, they're likely not going to get much but a cameo.