that app has accurate shadows:
It also enables an object such as a leaf to be in front of the 3D asset.
There are controls to adjust the character positioning, including hair positioning.
The original post by @fyaosx dealt with moving the images from the THETA to a third-party server. I’m assuming that he wants to add 3D assets into the images, at the third-party server site. For example, the plug-in could transfer the images to an AWS instance and he can then allow his users to configure the assets and images in the AWS instance.
Another possibility using the Hatsune Miku concept is to use a separate mobile app to exchange data directly with the plug-in, eliminating the need for a third-party server.
Remember that the plug-in can serve up HTML assets from the camera with a library such as NanoHTTPd. A companion mobile app could take the assets and cache them on a separate mobile device.