No you can visit as a tourist for a few weeks max.

https://embassy-finder.com/travel-with_mexico_pass...

Of course.

No one needs a visa to enter London, you get a visa to enter a country not a city....and Mexicans who wish you travel for a holiday to the UK do not require a visa to do so

you don't need one to come as a tourist.

https://www.gov.uk/check-uk-visa/y

Yes.

yea but as soon as there in they're not gonna get deported