Matplotlib and Seaborn are very similar with Seaborn being built upon Matplotlib. Matplotlib is great for a wide variety of visualizations while Seaborn is good for statistical data visualization. Bokeh is great at creating data visualizations that are web ready and could be embedded into web based apps.
The relational plot function replot() is used for displaying the relation between two variables and how they affect eachother. Ex: Making a scatterplot of years of experience vs salary. The categorical function catplot() visualizes the relationship between a category and a variable within the data. Ex: Showing average sales of products across different categories. The distribution function displot() visualizes distrubtions of variables within the dataset. Ex: Showing the demographic of a university
The Seaborn cheat sheet is a quick reference point in case a developer is curious of the Seaborn flow without having to look at the docs. Figure Aesthetics and Plotting with Seaborn are sections that provide good information to devs.