Best way to maximize Insider XP between 3 consoles?

separate achievement list are the best way to do things to maximize the value of a title.

Games cannot be made play anywhere after the fact.

Unfortunately there is no way to change the Windows LIVE ID without a console. This is to maximize the security of the account. My best recommendation to accomplish what you'd like would be if you have a friend with a Xbox 360 console, recover both accounts
to that console, then change the Windows LIVE ID in the order listed above by Mister Gwyther.

I very rarely have a console update get in my way. If you're an Xbox Insider and don't want to keep receiving those updates, leave
the Insider program.

You can also set your console to automatically update itself and your games & apps by following these instructions.

Game updates are pushed out by developers, not by Xbox. The majority of updates add new content or fix bugs, both of which maximize your gaming experience. All platforms (PlayStation, Xbox, PC, Nintendo, Mobile) experience system and content updates. Ultimately,
the best way to keep them from becoming bothersome is setting your console to update automatically.

bloodborne is a third party game so it should be on xbox by rights third parties should want to maximize who plays there game and the best way to do that is get it on as many formats as possible

As far as I am aware, no, no one particularly knows because they put out updates as they are ready to be tested. Sometimes they can come almost daily or sometimes it can be almost a month between updates. The best way to know for certain, is to check the
Insider App for content updates daily like I do. That way you'll never miss an update or a preview.

There's also a little FAQ page for future questions.

https://support.xbox.com/en-US/xbox-one/console/xbox-insider-program