Plotting with Seaborn

I find seaborn.objects much more pleasant to use that matplotlib or the default Seaborn interface. Therefore, some useful references:

• Tutorial
• API reference

Extensions I’ve found:

• Rolling sums
• Seaborn objects recipes

Questions I have:

• how to take an average (like so.Agg()) over both x and y axes, and over specific columns? e.g. if I have multiple runs with different hyperparameters (columns C1,C2,C3) and different methods to compare (C4-…), how do I plot the maxima over C1-C3?
• how to mix faceting and pairing not in the obvious way? e.g. facet on row="A" and ‘pair’ along the columns y=["B","C"], so that we get 2 different y axes in the same row (but ideally shared across rows)