I'd be fine allowing a Kamerel to "enter reflection" with any objects they can carry, so long as they can't transport non-kamerel living creatures.
The idea of the mirror gear was more about whether the Kamerel can make stuff while in the Plane of Reflections than about what they can take into it, sparked by the line "The kamerel prepared the
scry and
transport mirrors called for in the following encounters long ago—they brought them along out of reflection, where they’ve spent the last few millennia".
If everything in Reflection is immaterial, the Kamerel would have to have taken all these magic mirrors with them when they entered Reflection thousands of years ago, but I get the feeling they "prepared" these items
while they were in Reflection. These mirrors take a
full year of preparation to make. Did they really have enough time and spare resources to manufacture a large stockpile of them at the same time as they were fleeing the Rilmani?
Anyhow, as I said earlier, the main issue is we need to nail down the nature of the Plane of Reflection and what state the Kamerel exist in while they are resident to that dimension. Here's a few problems I ran into while trying to write up a SQ for the Kamerel's Pass Into Reflection ability:
- Do the Kamerel in Reflection have a material existence relative to each other? i.e. can they touch, talk, cast spells etc on each other?
- What happens to them when the observer giving them reality looks away? I'd guess they either vanish until someone looks at them again or are instantly displaced to another reflection.
- What can the observer see of the kamerel? The text says "Their entire existence consisted of hiding their ever-so-slight movements so that they were nothing more than a brief flicker in the corner of some mirror-gazer’s eye, so subtle that the viewer almost never noticed them". That suggests they could show themselves to observers, but are using spells or stealth to conceal themselves.
- What counts as a reflection? It's not just mirrors, but "other shiny places" create spaces in Reflection a kamerel can exist in.
- Does the observer have to see the reflection clearly? If the glass is foggy, or they're looking at the reflection of something very far away or hazy, such as a distant mountain, does that exist in Reflection, and how does the Kamerel perceive it? If the observer views an indistinct reflection, does the Kamerel see a blurry equivalent in Reflection?