John Theune writes:

Marble Canyon is about 45 miles away from the Grand Canyon in Marble Canyon

Marble Canyon is part of the Grand Canyon, and part of the Grand Canyon SFRA.

Cliff Dweller's Lodge is also in Marble Canyon about 40 miles from Grand
Canyon

See above.

Tuweep Cannot find anything about this one, maybe it's a made up one in MSFS

Are you not a pilot? Just look at the Grand Canyon VFR chart--as I did.

Grand Canyon Bar Ten is also outside of the Grand Canyon area about 56
miles west of Grand Canyon airport ( which is also not in the canyon but
rather on the rim to the south of the canyon.

This airport, like Tuweep, is well within the canyon, and well within the
SFRA. Look at the chart.