Here's a few tidbits to consider or ignore at your leisure:
Masks can technically be forged to look however you want, but they gotta be usable as a mask if you want to access their mask power. Getting a specific mask power requires melting down a specific combination of Kanoka discs.
Matoran/Toa/Turaga are incapable of romance. Other forms of love are okay though.
I might be retarded 'cause there are already perks in the CYOA that address this.
Toa of Water, Lightning, and Psionics are exclusively female, although a male Toa of Psionics, Orde, was built somewhat early on. His aggression led to all future Ce-Matoran being built as females. The rest of the elements are exclusively male, besides Light and Shadow, which can be either. If you want, you can handwave any contradictions as you being part of some beta test (like Orde), or having had a chance encounter with the Ignika, speaking of which…
The Mask of Life is a finicky thing. Few people are destined to be able to touch it without anything happening to them. Usually, it'll do things like make everything around you come to life (clothes, armor, floor tiling, etc), change you into a tool (e.g. a bug into a shield), or even another species (bad guy into a snake). Putting it on converts you to energy that it absorbs. RIP Matoro.
There's a bunch of other locations and eras in the Matoran Universe the CYOA doesn't mention, if you don't wanna limit yourself to major locations.
Alternatively, there's always Spherus Magna, after the planet's reunification. (After all, why would there be a Toa running around before the Shattering?) Maybe you could figure out a story there. I think the Ignika's in a dormant state from all the energy it used to quickly terraform the planet into something immediately viable, so it's probably safe to touch, for now.