Can I add LabPadre, Marcus House, What about it!? and other YouTubers into the article?

Unfortunately, no. The reason being that they are not notable enough. A notable person should already have a Wikipedia page (notable enough to be created) and have reliable sources covering them (notable enough to be mentioned). Sources such as YouTube videos, Musk's tweets, Teslarati, blogs, and more are not reliable, since there is no one to fact-check them. The few that are reliable are NASASpaceFlight.com and big news outlets in this case.

There is a Booster 6 thrust puck being shipped to Starbase! Can I add that to development history?

Sure, but it would be extremely cluttered with new-ish information being added to the end of the article. Only launches and RUDs (destruction) of test articles is added for that reason. SpaceX Starship development history is specfically made for documenting more detailed history, but please add reliable source to the event. Something as miniscule as a shipment to Starship might not be notable enough for inclusion, please discuss at the article's talk page.

Uh, these criticisms part are invalid! Can I remove them?

Short answer: Please don't. Long answer: These criticisms are valid, since they have valid sources from verifiable websites. We need everyone, including SpaceX critics, SpaceX (responsible) fans, neutral about SpaceX, and even never heard of it to work on this article, so that they are as neutral as possible. Neutrality, not praise, is our goal.

SpaceX Starship development history was merged with this article. Where do I put new updates?

The SpaceX Super Heavy and SpaceX Starship (spacecraft) articles are the current location for placing any new updates, so long as they are reliably sourced. Updates like FAA licenses, Mishap investigation closures, ect, ect, however, go on the article for the flight test itself. Major design changes (such as the v1, v2, and v3 versions), go on the SpaceX Starship design history article, after the previous version is no longer in operation. For example, the v1 -> v2 change will be able to be listed after the last v1 flight.