This used to stir up a lot of controversy a long time ago. Lavender Town and the information regarding it is a lot darker in the original game, and was slackened down in the localized American version.
The ghost appears in the Pokemon Tower because that's what it is. A tower for dead Pokemon. In fact, until you get the Sliph Scope, an time received in I think Saffron City, all the Pokemon in that tower appear as Ghosts, even the Ghost-type Pokemon themselves.
I haven't finished watching your videos, but I did get to the Lavender Town Syndrome part, in relation to the music;
I found this:
Lavender Town Syndrome, also known as The Lavender Town Conspiracy, The Lavender Town Tone, or The Lavender Town Suicides, is a series of creepypasta stories and videos that detail a conspiracy to cover up mass child suicides. These suicides were allegedly caused by listening to the first version of the Lavender Town Theme in the Japanese version of the Pokemon Red and Green games.
Origin
Introduced in Pokemon Red and Green[24], Lavender Town is the designated graveyard for deceased monsters and is known for its ghost sightings. The first edition of these games was released in Japan in February 1996. By the time the games were released in the United States two years later, the original music for Lavender Town, composed by Junichi Masuda[23] had been changed.[5] Since the ambience of the town was that of a graveyard, the music was relatively creepy, with players on gaming message boards Serebii[2] and NintendoWorlds.net[3] discussing this in 2008 and 2009. A remix[4] of the song appeared in early 2010, attempting to intensify its spookiness.
As for the Marowak, the game explains why you can't catch it. Because it's already dead, the Pokeball isn't able to catch it.
I personally found Lavender Town always to be interesting. And I am a believer of the Kangaskhan-Marowak-Cubone. Though I've always heard that MissingNo. was the code for Mew.
