With Rafael and Serafina, the pronunciation is the same though, isn't it? So I don't see why Americans would have an issue with it. But, in my experience lots of Americans do see foreign names and completely lose their heads. My first name is Nikolai and I could never get people to pronounce it the proper Russian way. For some reason, even Anglicising it and making the first syllable rhyme with Nick, a good half of the people I meet have to ask me several times to clarify pronunciation. And they often think it's spelled Nicolai, which perplexes me.
The F instead of Ph does make sense in some names, if you're using it to highlight a different pronunciation -though I would read Filip as fi-LEEP because of the similarity to Filipe. I just don't know how successful it would be. Sofia with the 'o' as in 'off' instead of 'oaf' is nice, but it would need to be explained practically every introduction.
It's vexing, and I'm not in favour of Americanising everything (as indicated by my spelling)- but it's easier to pick a different name than deal with the explanations, imo.