Is it in the public domain?

[alexavargas]

Hello!

I got some sheet music that I'd love to share with IMSLP, but I'm not sure about its status, you'll see:

The composer (a very dark and almost unknown figure) died in the 17th century, so by definition, his work is in the public domain, but...

What I have is the first (and only) modern edition with realized figured bass, published several years ago by a modern researcher.
Is it legal to create my own typeset of this piece, avoiding the editorial realized figured bass? is it still considered public domain?

And I also have another piece by the same composer but from a senior thesis in the same conditions.

Thank you!