Hi, I'm Matt and accepting your challenge for the project (have 20+ years of software development).
The application you require is possible/meaningful to develop using only cross-platform programming frameworks. My choice would be Kivy.(org), a Python programming language based graphical development framework. It can generate applications for Windows, Mac and (Ubuntu and similar) Linux distributions, then Android (Kindle as a variant, right) and IOS.
I have the right skills, knowledge and also a gamification certificate from Coursera (and studying knowledge management, PhD) so 90 days to develop is achievable.
Please provide more details to create extended plan. It would include my contracted designer work for graphic parts (e.g. icons, dialogues, other images), list of functions and other requirements (what cloud/web services you plan/are needed).
Looking forward to your reply,
Matt