Can 3rd row seat be added to TRD Off Road or Trail after purchase?

Live in the Ozarks of Missouri work as a Gov Contractor in NE Africa.
Have a King Cab 2006 Nissan Frontier SE 4x4 that I'm tired of being cramped up in after 12 years of ownership.

Looking to buy a 4Runner 4x4 (2015 - 2018).

A couple dumb questions for anyone that wants to chime in. I already searched.
I want a 3rd row 4x4 w/ a locking rear dif. Doesn't seem that Toyota offers that.

Can a 3rd row seat be added to a TRD Off Road or Trail after purchase?
Any issues with adding lockers (Arb or other) to a SR5?

Nissan makes it difficult to add a rear locker to non-Nismo/P4X or 6spd.

I have no kids but I have lots of friends - I could see taking 5 to 6 adults on drives. The small gals can fit in the 3rd row.

Couple SR5's I'm looking at:
https://www.cargurus.com/Cars/inven...text=RecentSearches_false_0#listing=215748732

https://www.cargurus.com/Cars/inven...text=RecentSearches_false_0#listing=220047548

https://www.cargurus.com/Cars/inven...text=RecentSearches_false_0#listing=225865191

 

Have you looked at the Toyota Land Cruiser?

 

The rear locker won out. Bought my 4Runner Off Road, new in June of 2019. Already have 15000 miles on it. Looked at some used ones but they were only a few $1000 less than brand new.

The 3rd row is no longer an pressing issue for me. Would be nice to have but not needed.

 

To answer OP's question, Yes, and I've seen pics here or on another forum, but it's probably not worth doing (what the person wrote after finishing the job) and it's easier to add a rear locker to the SR5P or the LE which already has a 3rd row.