Miners find most-recent block at nearly the same time.

Edit : The Tx's simply get recycled into a Mempool, and get carried through on a later stage, the Coinbase-tx is only spendable after one hundred block confirmations, which means that the Coinbase-tx can easily be discarded without implications.

Causing both valid blocks to be broadcast to the network, some nodes confirm the block from miner A, and add it to their copy of the blockchain, other nodes confirm the block from miner B, and add it to their copy of the blockchain.

This causes a temporary split in the blockchain up until one of both blockchains (The chain that went with the block from Miner A, and the chain that went with the block from Miner B) gets build upon faster.

In other words, whichever chain (A,B) receives the next valid block first turns into the longest chain, making the other chain (A or B, respectively) obsolete.

So far, so good, but ; Imagine a temporary split happens, which holds up for the next three blocks, in theory there are six valid blocks, meaning there are six valid Coinbase-tx's, as well as varying Tx's contained in each of the six blocks.

What happens to the three blocks that get discarded when the consensus returns to the longest chain ? Will the Coinbase-tx's as well as the different Tx's be "recycled" ? And if so, how ? I know that technically transactions are to be seen as valid whenever a certain amount of blocks get added upon the block in question, meaning one's Tx is "valid" once (I.e) six more blocks are attached to "your" block.

Using this leeway, the three discarded blocks and their content aren't to be seen as valid until they are "deep" enough, but what happens their content ? Are the Tx's reversed ? And how are the Coinbase-tx's returned ? Are they even returned ? The Tx's can just be un-done, correct ?

I hope I've painted the picture clear enough :)