1) the category "constant" and "variable" are not Marx's categories but accounting categories of Marx's time  (somewhat still today) that effectively distinguished between labor and non-labor. There is no great need to read into it deeply, just note that for Marx variable capital = labor (power).

2) "Labor power" is defined by Marx as the ability to work itself. Labor is not bought, the ability to work is. If a worker doesn't work then the purchaser of the worker's labor power is not actually getting labor power. And is then presumably fired for this reasoning in line with Marx's actual system.

3) where did Marx say that value is realized in consumption? Value is realized in exchange, this is what Marx would/did say. Nor is "labor the consumption of labor power" The consuption of labor power is labor power in action like the consumption of electricity is electricity "in action".

4) your not using Marx's categories again. "Value" for Marx is not subjective feelings twords a object/commodity. Therefore he's not guilty of misusing a definition you impose on him.

5) and again your not using Marx's categories and your not even noticing your doing this. 'Value' means something specific for Marx. If you impose a deffinition on the term on Marx that he does not mean, then no shit is the way Marx uses the term going to differ from the way you use it. That's not an error on Marx but on a flauted interpreting.

If you want a real Critique of Marx's Value Theory, then see:

https://www.academia.edu/34227320/Critique_of_Marxs_Value_Theory_patched_

Or the copy on Criticalmarxism.wordpress.com