For these two posts, the description does indicate that genderswap is included, but I'm not sure if that applies to all four characters or not, since both Satori and Youmu still look like girls with very girl clothing. I'm running under the assumption that only Remilia and Momiji are boys; feel free to correct me if I'm wrong.

andlabs said in comment #2577732:

For these two posts, the description does indicate that genderswap is included, but I'm not sure if that applies to all four characters or not, since both Satori and Youmu still look like girls with very girl clothing. I'm running under the assumption that only Remilia and Momiji are boys; feel free to correct me if I'm wrong.

This artist tends to make the genderbends pretty unambiguous and has done FtM/F pairings before. I'm pretty happy saying these are 1boy and 1girl each.