Do +Meteor damage and Nilfur's Boast boots affect Tal Rasha Meteors?

Builds (at least the ones I find on /r/Diablo3 and /r/Diablo3Wizards) are actually centered around just these.

As someone currently running that exact build (On PS4, so I cannot link bnet profile), I can tell you that both +Meteor damage and Nilfur boots absolutely do boost the effect. I got my Nilfur boots after completing my Tal Rasha's set, and saw a decent increase in damage. Additional information from the above reddit sub-forums as well as the Diablo 3 forums confirms this.

As far as I can tell, the proc from Tal Rasha's set behaves as if you had cast the meteor yourself with the appropriate element.

I'm running with Tal Rasha's and got the whole set, and yes, they are using the +Meteor bonus from items, as well as the 100% from the boots.

Here's a guide to the build, and a good documentation on it: icy-veins.com

Here's a little snippet from it, regarding your question:

Introduced in Patch 2.2, the new best friend of the Tal Rasha set are the Nilfur's Boast boots. Doubling the damage of Meteors by default, and with the potential to triple your Meteor damage against three or less enemies, these boots are non-negotiable for a Tal Rasha Wizard. Naturally, seek out Meteor % bonus alongside the usual primary stats.

But as @Thebluefish says, take a look on /r/Diablo3 and /r/Diablo3Wizards for more info om builds, and setups.