How can you send a transaction directly to the memory pool? Is it possible to send a transaction to the bitcoin memory pool directly to have it mined without validating it?
There is no such thing as "the bitcoin memory pool". Every node has its own memory pool; it is not shared across all nodes in the network. A node can certainly add a transaction to its own mempool without validating it, but you cannot force other nodes to add a transaction to its mempool without validation. In fact, you can't force a node to add a transaction to its mempool, nor can you force a node to accept anything.