Merging multiple videos in a template/layout with Python FFMPEG?

I'm currently trying to edit videos with the Python library of FFMPEG. I'm working with multiple file formats, precisely .mp4, .png and text inputs (.txt). The goal is to embed the different video files within a "layout" - for demonstration purposes I tried to design an example picture:

The output is supposed to be a 1920x1080 .mp4 file with the following Elements:

• Element 3 is the video itself (due to it being a mobile phone screen recording, it's about the size displayed there)
• Element 1 and 2 are the "boarders", i.e. static pictures (?)
• Element 4 represents a regularly changing text - input through the python script (probably be read from a .txt file)
• Element 5 portrays a .png, .svg or alike; in general a "picture" in the broad sense.

What I'm trying to achieve is to create a sort of template file in which I "just" need to input the different .mp4 and .png files, as well as the text and in the end I'll receive a .mp4 file whereas my Python script functions as the navigator sending the data packages to FFMPEG to process the video itself.

I dug into the FFMPEG library as well as the python-specific repository and wasn't able to find such an option. There were lots of articles explaining the usage of "channel layouts" (though these don't seem to fit my need).

In case anyone wants to try on the same versions:

• python --version: Python 3.7.3
• pip show ffmpeg: Version: 1.4 (it's the most recent; on an off-topic note: It's not obligatory to use FFMPEG, I'd prefer using this library though if it doesn't offer the functionality I'm looking for, I'd highly appreciate if someone suggested something else)

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