Can TOGAF Architecture Method (ADM) be seamlessly integrated with ArchiMate. Are there any tools out there in the market that supports this kind of integration and modeling authoring process?
Yes, absolutely possible! And in fact, there are some examples around and people in the industry are already practising it this way!
Information from the Open Group
TOGAF ADM can be well integrated with ArchiMate and, in fact, that was one of the reason why ArchiMate designed for. Open Group has an article about the feasibility of TOGAF ADM and ArchiMate integration
Example from Software Vendor
Such kind of implementation from the Software Vendor – Visual Paradigm also illustrated this by integrating the two open standards TOGAF ADM and ArchiMate 3 into one unified software platform.
Here is an article for how to: Use ArchiMate tool with TOGAF ADM seamlessly by using the Guide-Through Process. The screenshots captured from the software are illustrated as follows: (Source: TOGAF Guide-Through Process illustration)