Did you try running the https://github.com/allegroai/trains/blob/master/examples/reporting/Allegro_Trains_logging_example.ipynb ? I just ran it twice against a Trains Server of the same version, and I can see all plots in the compare...
As for the experiment name, In some plots, the UI will display plots side-by-side, and than the experiment title will show on each plot. In other cases, each experiment will be shown as a series in the graph (perhaps this was the case in your plots?)

Experiment names marked in red

Yes

With matplotlib I only get the suptitle

And what is the Trains Server version?

VirtuousFish83 see below what I see when I run the example twice and compare:

Hi VirtuousFish83 , are you using your own installed Trains Server?

And the comparison for the confusion matrices without the name of the experiments

And an example of the missing comparison:
the two experiments 2. plot on the first one 3. plot on the second 4. comparison plot only shows other plots (only the confusion matrices)

0.16.1-320