You are creating a product (mobile application) for which you/your company will continue to earn money (as it has from the print version). And you are consulting free service, an expert panel of volunteers. Somehow this seems a bit out of whack. I hope if what we are offering you turns out to be of value you/your company will make a substantial donation toward the maintenance of this service.
Besides my credentials as a linguist, I also bring many years experience in (digital) product development. It's not often that a question here makes use of my product development expertise.
Professor Papen's advice is sound. Note that what he suggests is providing different information (metadata) about words depending on the language being viewed.
I'd also suggest you engage in a bit of observational (qualitative) research with a) avid users of your current application, and b) novices to your application, in order to learn how they actually (wish to) make use of the tools you provide and so that you can make sure the mobile tool provides at least the same value as the print document, and potentially more. You can also create simulations of the eventual product, rapidly, and determine how layout on the screen (form) and key information (content) interact with each other. These simulations can be rough paper prototypes that you ask your users to try out, and later digital prototypes as well.
Notice also with a mobile application, you don't need to make it perfect on first release, as you can adjust, and enhance it in version 2.0. There's strong advocacy these days for the "mobile first" approach (search on that phrase) - design for a mobile device (or all mobile devices - phones and tablets) and the desktop/laptop version is secondary. This approach asks your team to rethink what is necessary, what must be seen on first screen and what might be available on additional screens.
Nancy J. Frishberg
For English, you might want to include Part of Speech (noun, adjective, verb, preposition, adverb, modal, participle, determiner, etc.). You will not need to specify gender for nouns since there is no grammatical gender in English. I'm not sure what you mean by 'verb type'...but in English, verbs are not marked for 'verb class' (as in French or Spanish). Nouns are not declined in English,so that information is not necessary.
For French, besides Part of speech (as above), you should consider providing gender for nouns (important for appropriate selection of determiner and adjective form), also provide irregular plural forms (for ex. animal/animaux, oeil/yeux, etc.). For verbs, you should provide conjugation class (-er, -ir, -re, -oir)and state whether they are 'regular' or 'irregular'. French nouns are not marked for case so declension model is not required.
I will let my colleagues more familiar with Spanish, Portuguese and German answer the specifics of your question regarding these languages.
Robert A Papen