hsuzue:

I don’t care the network in detail.


This seems to be the most important detail in order to give you some ideas. 
Generally, it’s possible to combine multiple inputs, but without a proper description, I cannot give you examples.
E.g. your MaskRCNN models would already give you the predictions, while the image seems to feed (some) predictions with an additional input to a fully-connected layer. What should this fully-connected layer return?