Practically it's not possible! A product can born earlier than its underlying technology. That's the reality! However if you say that the concept of bitcoin was formed first and then Satoshi formulated the concept of blockchain, that may be a possibility. But when the actual product (bitcoin) is build and published, the underlying technology (blockchain in this case) mush have been built before the actual product. It can't be the other way around because technically it is not possible to build bitcoin earlier than blockchain. Can only happen during the conceptualization period, not during implementation!

Logical thinking! I always point out that Bitcoin is created on Blockchain technology when I explain it to some people, so it's why this topic and the OP point of view is a bit confusing for me... simply Bitcoin is built on something, and that something is Blockchain... so it must come first!

I guess that only Satoshi can answer this question... what was the first thing that felt on his mind, Bitcoin as Bitcoin, or technology that can be described as a data structure that holds transactional records while ensuring security, transparency, and decentralization in the same time! We can try to guess what it was, but if we follow the logic it would be Blockchain first, and later Bitcoin... after all that, we have many others that used the same technology to create something different!