dzham I think we're aligned, but still researching how/when to integrate multi-sig in a way that makes sense. I think the use case for security depends on the amounts -- small wallets for new users exploring may not require it (e.g., sub 100 XLM) while larger stakes would need greater security like multi-sig, backup seeds/recovery process, etc. There are also some alternative features we're going to explore to detect/fight ATO in addition to multi-sig, not sure yet on order of operations.
Re: collaboration, it's a good question. To be honest, we're using the build challenge as a forcing function to get our hands dirty and learn more about Stellar. But setting that aside, I also think some competition here is good for the community, Stellar users will have more choice and it'll force all the wallets to be better when there's competition for users. I also think given the wallets we're seeing we think we can do some more novel/radical things in the future, just not sure about in time for the build challenge -- but we'll try!