Assertion #1 is problematic here. As best I can parse it, you are saying, the human embryo is [of human origin]. That is very different from "the human embryo is a human." Most scientists and non-religious scholars and philosophers would disagree with the latter statement.
Assertion #3 is also problematic. You need a definition of alive that is both non-arbitrary and does not include skin cells, cancer cells (which can reproduce indefinitely), etc.
Assertion #4 is very interesting, and I think has been well-treated by other commentators.
Basically, you have asserted a syllogistic like statement that completely falls apart when examined closely. The attempt to save it by asserting that assertion number 1 is true by definition does not work. Assertion number 1 is only true by definition for trivial interpretations of assertion #1 (i.e., the human embryo is a collection of human cells).
Assertion #3 is also problematic. You need a definition of alive that is both non-arbitrary and does not include skin cells, cancer cells (which can reproduce indefinitely), etc.
Assertion #4 is very interesting, and I think has been well-treated by other commentators.
Basically, you have asserted a syllogistic like statement that completely falls apart when examined closely. The attempt to save it by asserting that assertion number 1 is true by definition does not work. Assertion number 1 is only true by definition for trivial interpretations of assertion #1 (i.e., the human embryo is a collection of human cells).