Saturnine Terminators Proxy

Hello I've like never proxied models before and I had a couple questions about how I could proxy a saturnine praetor as a terminator captain and saturine terminators as centurion devestators.

1. For the praetor I want to use the warhammer but the terminator captain doesn't have a hammer as a weapon option so should I use the axe or just say fuck it and go for the hammer.
2. What weapon options for the saturnine terminators would work best for centurions and I guess what is the best centurion loadout (this is for a salamanders army btw).