I kinda have to wonder: We're used to the PokemonSpeak in the anime series, but here, they just growl, roar, and make other sounds like other animals would. Why is that though???
Probably to hammer in the point that this series is not like the regular anime.
This is based more on the games, in which the majority of Pokemon don't use PokemonSpeak. Even Pikachu didn't start saying its name in the games until Pokemon Yellow
Where was Red able to get the Pokedex data for the other two starters? Wouldn't they have needed to be caught?
Through trading I presume. After all, how else does one get a Gengar and Alakazam in the games?
The anime itself is not a perfect rehash of the gamnes; Red for example caught a Caterpie and Spearow before entering Viridian City and encountered a Nidoran before said city as well, which does not happen in the games. whose to say that wild Bulbasaur, Eevee, ect aren't around in this anime verse?
Marowak was killed by an electrified prod. Marowak is a Ground type, which makes it immune to electricity, and can even have the Lightningrod ability, which also makes it immune to electricity. Did the physical force of the prod kill her?
On the same note, how did the kid at Fuji's Pokemon home know how Cubone's mother died? Fuji found Cubone after Marowak was killed.
The original Japanese version mentioned immunities or abilities exactly zero times - implying that despite being more faithful than other adaptations, Pokémon Origins ignored them. Is this different in the dub?
Abilities were not implemented until Gen III, though.
There could be a grimmer interpretation that Marowak was immune to the electricity of the rod, so the Rocket Grunt simply had to beat it to death.
And if Cubone's helmet is its mother's skull, where did it get its helmet from?
The same way as any Cubone bred from the Daycare Center get their helmets in the games. Despite what the Pokédex states, Cubone's helmet skull is not made from their mother skull ever since Generation II. Not to mention that none of the Pokédex entries in Origins are readable anyway.