Terribly sorry for my absence. Had university stuff to take care of and I got sucked in by Tsukihime afterwards.

[@Nanashi Ninanai]
I don't really see any problems with using homunculi, but I think setting up a place to make them would be difficult as they are pretty advanced from what I've seen. Although, since Tianzi's are low quality then maybe she doesn't need a workshop that advanced. I do recommend care with transplanting circuits. Medea did that once to Shirou and he got pretty messed up in the end.

[@NachoBachoPacho]
The character is fine, there's no real problem with his magic either. What you probably had trouble with is the difference between origin and alignment or element. The origin can be pretty much anything, but the alignment is well defined on what it can be. He can have holy light as his origin, but his alignment or element needs to be added.

There are seven alignments in total, with the normal or physical ones being earth, water, fire, wind and sky, and the non-physical or imaginary ones being emptiness and nothingness. Sky makes up celestial bodies and is essentially ether, emptiness is "which is possible but is not in the physical plane", also called imaginary numbers, and nothingness is "which is not possible, but materializes".

Something important, however, is that one's alignment can be changed through training. For an example, Sakura was emptiness and turned into water by the Matou. One's origin can also change, but the only example that I know is Shirou and his was replaced by "sword" when Avalon was implanted on him. So from what I can tell alignment can be molded, but origin would have to be replaced by a strong force. But since there's little detail on this I guess you can keep his background the way it is, just add an alignment to complete him.

Also, as Dawnscroll said earlier, one can have more than one alignment.

I got info about this in here btw.
http://heavens-feel.com/completematerial.html

[@Chotgoriin]
What exactly do you mean by Mix-Bloods? If you mean something like half-human half-demon you'd better wait on Dawnscroll.