Well... realistically speaking:
- When you record something that's underground and covered by a building, it will create a lot of weird echoes from inside and around the building.
- Well= water water= weird noises
- Frog men- maybe in the military... but actual frog person, that just can't happen
- Don't make an article about something where you claim it's factual but you then say "legend has it"
- Man-made well= not bottomless

Don't worry mate, it would probably be debunked if it wasn't making so much money off of tourists.