Your gateway to endless inspiration
With this fandom being so chaotic, sporadic, and creative I have seen/read many great ideas and interpretations of the shows lore and characters. Here are a few of my personal headcanons that have for the content of Miraculous Ladybug.
1) I have liked the concept of true holders, those who embody the aspect of a certain miraculous. I imagine that while anyone can bond with a miraculous or wield a miraculous, the closer you are to being a true holder the faster and better the person can adjust with that miraculous. Also being a true holder makes the person able to unlock new abilities with the miraculous slightly faster than those who are not.
2) Kwamis are able to sense if someone is a true holder or not (though this mainly goes for if the person is their true holder, but any kwami can tell if a person can connect with a miraculous just not which specific one). This sense does have a limited range and the farther away the kwami and holder are, the harder it is for the kwami to pinpoint them.
3) With the miraculi, the longer a person wields the miraculous; the more in-tune they become with it. This goes for both those who are true holders and those who are not, but the true holders are just able to bond quicker and in a little more depth. With enough time and training, the holder and kwami might even be able to telepathically communicate when transformed.
4) As the bond between kwami and holder strengthens, eventually the time limit after the use of the special power lengthens in time. (My explanation of why Ladybug and Chat Noir have only five minutes while Hawkmoth has a lot longer since the age thing is odd. Since Hawkmoth has presumably had the butterfly miraculous for a long time before LB and CN got thiers.)
5) Since a miraculous seems to only be limited by the imagination/will of the holder, as time passes, holders are able to unlock different powers/sub powers that are able to be used on occasion. The sub powers are smaller in scale than the "special" power or the potion power ups, but are still big enough to be noticeable.