I highly doubt it fits the 3-months-project frame, especially given how impactful and sensitive an area of the skin(s) interwikis are.
I'm not sure if it fits on a 3-month period, but I think that some aspects may help to it:
- I agree that interlanguage links are a sensitive area. But this concern can be solved by adding the feature by means of BetaFeatures, so that our community members can opt-in to test it and see how it works in practice for all kinds of articles.
- From the technical side, the most complex pieces are already available (e.g., getting usual languages based on geo-ip and previous selections, language selection UI) which would help to speed the development.
Pau