Hedy Lamarr is an interesting choice - she doesn't get portrayed much in SF although there was someone a lot like her in the second series of Agent Carter, who ultimately turned out to be a villainess. The real person did have a history of walking away from commitments when she found something better, which might not be ideal if you want someone completely trustworthy.

Julie d'Aubigny would be an excellent companion with a strong River Song vibe. If you ever run into Madame Vastra and Jenny she'll probably want a threesome...

Don't know much about the others, but it sounds like a good team.