meaning in context - Do "twice as high xxxxx as" , "twice as high" and "twice higher" mean the same thing?

What do the following sentences actually mean? Are they the same in meaning?

1. The cost of living is twice as high in New York as it is in Tokyo.


2. The cost of living in New York is twice as high in Tokyo.


3. The cost of living in New York is twice higher than in Tokyo.


4. The cost of living in New York is two times higher than in Tokyo.

If they have the same meaning, then can I actually use them as a basis for composing other sentences having the same meanings? Such as:

1a. Your child is a hundred times as adorable as your pet dog.
1b. Your child is a hundred times adorable than your pet dog.

2a. Her room is twice as large as mine.
2b. Her room is twice larger than mine.