his mini map will be easy to make, but can decrease the performance of your game in some situations, also, it don't use plugins.
It's simple, you can make an array of your screen, placing invisible tiles on the screen, at the foreground (the top layer, that with parallax 0,0), then, check if any tile if overlapping any family.
Then, replicate it as a chest board on the corner of your screen, like you did.
This is not the best way, but I'm sure you can work with it.
I'm currently working with a different version, where I place on the corner of my screen a reduced version of my canvas (it's hard, because you'll need to printscreen, make the puzzle, and then reduce it). After if, I do the player position on the minimap by checking his position on the screen and using a correlation.
Right now I'm improving it to zoom the map and cut the edges to make sure the minimap viewed is inside the minimap area (everything bigger than the minimap area will be made invisible using webGL effect), because the minimap is larger than his area on the screen.