1970 frame cross members

[Chevrolet9279]

ok guys i have been getting down to basics and i am wondering if anything is missing?

only 2 cross members or are they called cross stills?

if there is only 2 that are there does anyone know where to buy replacement?

Does anyone else see anything else im missing? for basics?

and while im here any suggestions on.. por 15? chassis saver? KBS coating?
for frame?

thanks