The FBI isn't asking for Apple to give them the update to apply themselves. They're asking for Apple to apply the update. To brute force another phone, the FBI will have to go back to Apple.
Sure, but the legal precedent will make this a rubber stamp in future, and will mean that Apple can't reasonably resist such orders from other governments.
This case does not establish any precedent. This is a well-established power that has already been used to access iCloud data and extract unencrypted data off iPhone running older versions of iOS.
Such as? For an example to the contrary, see rayiner's comments on this issue. The only people I'm seeing that think this case is precedent-setting are tech bloggers who don't know any better and lawyers who were given a short time to respond and didn't know what the FBI was actually requesting.
The only restriction on this law that Apple could claim (aside from legally out-there options like equating writing software to forced speech) is "unreasonable burden," but this is something that almost any of us could hack up in a day given access to Apple's release build system.