are all lcd "screens" created equally in televisions?

Answer 1

Definitely no.

Panels are different (different contrast, response time, etc.)
Video processors are different (affects scaling, color reproduction, etc.)
Video know-how; even if two manufacturers use the same panel and same processor; the picture quality may be quite different.

Answer 2

no - there is a big difference between the "made in china " brand that Walmart sells and a sony, Panasonic or larger manufacturer (even if they manufacture in China) basically if you have never heard of the brand name before stay away from it.