Children's use of educational videogames is a growing at-home trend and has become a relevant classroom supporting tool in the teaching-learning process. The increased attachment to video games has hastened the creation of "learning through play" applications. The development of these applications requires the creative production of content using characters (avatars) playing distinct roles to engage people with the game. Evaluation tools need to be designed to understand and improve this engagement. This study aims to explain the design and development structure of research tools such as online personalized questionnaires and dashboard platforms used to populate data in a cloud for evaluating games' usability and avatars' preferences. The paper revises the applicability of three research tools tested to analyze five different graphic lines games series and the archetype of their designed avatars. The MIDI-AM educational videogames series for mobile applications is the case study examined. The need to evaluate the avatar preferences before or after playing the games to find correlations with the usability trends is present. Comparative results between the three designed research tools will help solve issues about different viewpoints between designers and producers concerning graphic lines used in educational games production and the correlation with game use preferences. The research is relevant for graphic designers, producers, and creative experts to develop well-informed styles and avatars for children's digital games. Also, the practicality of using the proposed research tools to analyze videogame and characters' preferences is confirmed.