  This work establishes a versatile theoretical framework that explicitly
describes single-photon subtraction from multimode quantum light in the context
of non-Gaussian state generation and manipulation. The treatment focuses on
easy-to-implement configurations in which no mode-selective operation is
available and evaluates features and advantages of scheme where only simple
filtering stages are employed on the experiments. Such configuration, by
considerably reducing the experimental overheads, makes experiments involving
single photon subtraction easier to be implemented. Obtained theoretical
framework allows retrieving, given a multimode input state, optimal conditions
required to herald and then to detect non-Gaussian states, providing a
practical and powerful toolbox for experiments' design. The application of the
proposed approach to the case study of Schr\"odinger kitten preparation
starting from a frequency multimode squeezed state illustrates the impact of
the derived theoretical tools.
