About the verification that he said. I always thought that the first pokemon you encounter will have the desired IVs from hitting the seed, but he says that the pokemon in the egg and a caught pokemon will both have the desired IVs from the target seed.
1. Is this true?
2. Does that mean that every pokemon obtained will have the desired IVs (2nd pokemon encountered, 3rd, etc...)?
Yes and yes again, unless you move onto a different IV frame, which can be done by walking 128 steps.
No, this is wrong, assuming that what Deltablazy means by 'every pokemon obtained will have the desired IVs' is that all Pokemon will have the same IVs. What Tesseraction is saying is that the egg will have the IVs (modified by inheritance) from frame 8 of the seed, and the Poke caught directly after getting the egg will have the IVs from a later frame (normally between 14 and 20) of the same seed. You can use those IVs to check that you hit your seed without wasting time on hatching the egg.
Any subsequent Pokemon caught after that will have IVs from a very high frame due to the previous battle(s) advancing the IV RNG, which is also a source of battle randomness.