In case of AXI4 lite protocol,whether BValid should be asserted before WVALID signal deassertion? what is the legal case?

In specification it is mentioned that WREADY signal can wait for AWVALID and WVALID signals.

Does it mean that WREADY signal should be asserted only after assertion of AWVALID and WVALID signals.

What is the relation between these signals?

and performance…

Difference between axi_4 and axi4_alite?

what are the possible values of strobe for a half word transfer in AXI4 lite? 

Are these following values on WSTRB valid ?

-1001

-0101

-1010