I (Mar) learned animation in Tokyo, and speak fluent English/Spanish, the latter being the one used for this project.
True, Nacho could get quotes from some other animation studios in Spanish too, but he was about to give up seeing their quotes. However, I talked with them through video calls and chat showing plenty of examples to understand the key needs of the band.
Together, we discovered that thanks to the "old-style" they wanted, there were ways to adapt the animation aesthetics to make sure they received a high-quality product at their budget and desired deadline.
We would cut animation drawings by sliding the characters around as in many classic anime endings, keeping complex animation for special scenes.