While there is no shortage of opinions re: Biblical eschatology we can give you a few things to consider and test.
We do not see any indication in the scriptures that we will be in the NJ during the 1,000 year reign. The idea is that we will reign on Earth, with Messiah Yeshua, for 1,000 years in the Land.
The rest of humanity also lives in the 1,000 year reign, but we rule over them as the "law (Torah) goes forth from Zion."
Yes, they can be saved, and yes, they also live on Earth. Most understand that the lifespan of those in non-resurrected bodies in the 1,000 year reign will have long lifespans. For example:
No more shall there be in it
an infant who lives but a few days,
or an old man who does not fill out his days,
for the young man shall die a hundred years old,
and the sinner a hundred years old shall be accursed.