PI Application with multiple dockers, networking and python2 dependency

We have an application on a PI 3 that involves multiple containers that have network connectivity, but
the application software is still depending on Python2.7. No chance to update that to Python3 soon.
Is it still possible to containerize this whole OS environment and run that container with the name connectivity as the pure OS version on the PI 3?

Hello, sorry I am not sure I completely understand the question. We have recently discontinued support for python 2 in our base images (have a look at https://www.balena.io/blog/deprecation-of-python-2-base-images-in-balenalib/ for more info) But you should still be able to use the python 2 base images with an appropriate tag.
We do however recommend updating to python 3 as soon as possible, since the base images will not get updates and fixes which might cause issues in the future.