I’m no Nickt of course but here’s a bunch of stuff I made for my hack. Feel free to guess as to who and what they are.
They look like they’re spliced nicely, but it seems quite obvious who they are at first glance. You can go further than splicing if you want to. There’s nothing stopping you from making Bartre’s nose not as ugly, taking away Rath’s ear ring, or making Neimi’s eyes a little smaller. Just invest a little more time into customizing them with Photoshop, Usenti, or whatever, and they can look really nice.
I’d say that’s a good start. Go from there.
Remember that fe7 and fe8 skin shades are different. Fe8 colours are also brighter and have more contrast. Stick to one type so that your portraits can look consistent.
I would suggest to use existing colour shades. If you really want to do custom colours take a look at the brightness and saturation values of the existing mugs. eg: Most of the time, the first colour is brighter than the second, take a look at mug nº10, the second shade on his shirt is brighter than the first shade.
Start using 3 existing mugs, one for hair, one for face and the other for armour/clothing. As the previous poster suggested mixing and matching like this makes your mug more unique.
Once you are comfortable, try mixing different eyes, mouth, nose and extra details, beard, ornaments, etc.
Remember to use Usenti when your mug is done to check for extra colours or missing pixels (there are some on mug nº7). You can only have 16 colours including the background.
Here are some skin colour ramps I made for fe8 splicing. It made my life easier so I hope it helps you too. (The shades on the right are slight variations of the ones on the left)