Miriam and Shanoa Similarities.

Yeah. From the moment I saw Miriam for the first time, I thought it looked very much like Shanoa. And again, like Shanoa, she's has a plethora of ways to dish out the damage instead of just using her basic attack.

But I still prefer Charlotte Aulin from Portrait of Ruin sorry not sorry.

Good catch. Also "Symphony of the night" and "Ritual of the night". It just makes sense when you take into account of what you wrote `(*∩_∩*)′

Maybe IGA was thinking about making a Castlevania which the female lead would be related to Shanoa and he reused the idea in Bloodstained.

Yeah, but Iga denies any relationship between Miriam and Shanoa. They're both similar because they're both strong female protagonists. Check one of the early posts where I posted a pic with Iga being interviewed about this.

As already covered by catastrophe, Miriam and Shanoa are too similar for it to be just a function "well they are both strong female leads". Considering, at least to my understanding, Shanoa was in part a tribute to/influenced by IGA's wife, its not exactly a shock that he would mine that well again - it means something to him. Granted, I thought Shanoa was one of the better characters in the Castlevania franchise so I'm not complaining (though to be honest I do like her character design more than Miriam's). I do hope Miriam gets to be a bit more expressive than Shanoa who had her emotions sealed away for most (or was it all) of the game.

Yes, Miriam kinda sorta looks like Shanoa. Almost like Juste kind of looked like Alucard. And Soma kind of looked like Alucard. And Leon kind of looked like Alucard.

I don't suppose they really have to look too physically similar.  There's plenty of differences between the two, but just enough similarities.

I think Miriam actually has a stronger Ayami Kojima influence in her character-design than Shanoa, despite being originally designed by someone else [Yuji Natsume]. (I think he's the one.  I could be wrong.)

I was actually surprised to initially learn that Ayami Kojima was not responsible for the character designs in Order of Ecclesia.  If you ask me, the OoE art-style didn't seem too "anime"-esque (though there are as many different manga/anime art-styles out there as there are mangakas, if not more).

Though I think, as has been said before, that the main similarity that Shanoa & Miriam share is simply that they are strong female protagonists. 

I noticed it almost instantly as well. I personally wondered if, given how frequently Shanoa appeared in the final years of the franchise, (Ecclesia, Judgment and Despair) she was a character IGA really wanted to explore but Konami canned him before he really got the chance; and if Miriam was perhaps his way of doing more with a character who's story was never allowed to really be expanded upon.

As for similarities when you get very specific yes they are different: Shanoa's hair is much longer, Miriam's face is rounder etc. But lets look at some broad strokes:
1. Both have large tattoos/marking on their backs and elsewhere on their bodies
2. Both wear outfits designed to reveal and emphasize said markings
3. Both wear outfits colored primarily blue and black
4. Both have amnesia, though Shanoa's is obviously more severe
5. Both character's stories involve fighting their former friends
6. Both characters are "Magic Knights" aka they can wield melee and magical powers with equal skill
7. Both use abilities taken in some fashion from the monsters they slay

I dont think its a huge stretch too see the pair as sharing more than a few things in common, though once we get the game the details, as well as Miriam's personality and how different she may or may not act will come to light.

Depending on how exactly the character will play, I'm sure that people might claim Zangetsu to be a "Soma clone".

Considering his "Ofuda" magic and sword, I think he may be more likely thought of as an "Alucard clone".