I think Bitcoin and Blockchain have been created together, although several platforms have used Blockchain, and from all the synergies with Blockchain, Bitcoin is the most successful.
Blockchain technology is the backbone of bitcoin and it is how the technology was introduced to the world. One usage of blockchain technology is cryptocurrency and there are other things that blockchain is applicable while cryptocurrency needs blockchain technology because it is where it is base from so in other words blockhain technology can exist without cryptocurrency while cryptocurrency cannot exist without blockchain technology so blockchain can survive without bitcoin.
Absolutely yes, Bitcoin is just one of the numerous applications on blockchain technology, the fall of bitcoin will never affect blockchain techs as it's the future technology.
That's right. Even if bitcoin falls, the technology is there and there are already many innovations that has been made that would improve the performance of bitcoin. There are first generation, second generation, and third generation cryptocurrencies.