While Marx hasn't gotten into any of that yet, I read this as foreshadowing that this labor theory of value will transcend all modes of production. That it isn't fundamentally changed whether a society is Feudal, Capitalist, or Communist.

No, the labour theory of value is only a thing in a society wherein the capitalist mode of production prevails. A communist society would be dealing with pure use-values while in a feudal society (not in the market-interstices) the focus was also use-values, not on value or its reflection exchange-value.

The quote you are commenting on specifically notes that the universal form of labour, independent of social development, is labour as creator of use-values. This labour is a constant for human society, whereas labour as a producer of value is specific to a world where the commodity-form is generalized.

The labour theory of value also doesn't acknowledge all work as labour, e.g. the persistent denial even to this day by many that housework, childcare, etc, is labour.

Marx seems to be of two minds on the LToV in Capital; sometimes he seems to actually genuinely believe that there is something fundamentally unique about human labour or that reproduction of labour-powers can be excluded from his analysis because family is a natural sphere, and sometimes he seems to be simply accepting the bourgeois definition of 'real' labour as a given for purposes of criticising it on its own terms and sees the concept of commodity-value as a purely social thing with "not an atom of matter".