The Initial Olmec Period is shown as 1,200-900 B.C. with its capital at San Lorenzo, which experienced cultural collapse around 900. There were "outrigger" settlements at places like La Venta, Laguna de los Cerros and maybe Tres Zapotes at that time. The same researchers say La Venta began to flourish around 1,000 B.C. Some believe its' influence continued to as late as 400 or 300.
What they call the Terminal Olmec and Epi-Olmec period ran from about 600 B.C. to A.D. 1. They say: "True Olmec culture drew to a close by 300 B.C., but a derived, epigonal culture survived north of the Tuxtla Mountains at Tres Zapotes...Ironically, although Tres Zapotes was the first Olmec site known, the nature of its Olmec occupation remains unresolved."
By reading several authors with varying points of view, it seems clear to me that what is called "Olmec" is subject to a lot of interpretation. Much evidence has either been destroyed or is yet undiscovered. My impression is that the archaeology to date has been pretty haphazard, probably due to economics. But the wet climate has also taken a big toll because much Olmec art and architecture were made of now-rotted wood. Usable stone was scarce in the La Venta region.
I agree.
Statues found in Olmec sites include all three of the racial groups.
Afrocentrist Dr Clyde Winters has a unique view of the Olmecs: Nubians And Olmecs