So, let’s say I get a transaction from four people all at once. Are these gonna hit different nodes? The order’s likely gonna be mixed up. I think that means mining nodes could slot them into different blocks, so their hash rate and nonce will be different too. Here’s my question: Is it common for Bitcoin transactions to create blocks with totally different transaction orders from various nodes? It seems to me that the key thing is hitting the right number for proof of work, and once that’s done, the block gets accepted by other nodes. Maybe the total number of transactions in the blocks matters too.
Once a transaction is broadcasted it is received by each nodes and they create a candidate block and add this transactions into the candidate in order they see fit, there is no actual arrangement required except that in case of dependent blocks where parents transactions comes before child transactions, or probably based on transaction fee which is not a protocol. So if all this transaction are ahead to one miners candidate block and the four transactions sent to you happen to fall in the block, if the miner gets the right nonce first then his block get added to blockchain after been verified by other nodes.
In simple term there is no prescribed protocol way to arranged a transaction except if one transaction depends on the order and the parent transaction gets added first, nothing more than the miner adding any of the transaction he pleases and as we know miners priorities that base on fees
It's not that each transaction goes to a mempool of different node.
Once you broadcast a transaction, it's propagated to the network and almost all nodes will receive that. If you received four transactions, almost all nodes will probably receive all those four transaction.
Miners prioritize transactions based on their fee rate and it's possible that a miner include all those four transactions in the same block.
Again, transactions are prioritize based on their fee rate.
Assuming the fee rate of transaction A is higher than the fee rate of transaction B, transaction A will be probably confirmed in the same block than transaction B or earlier.
Not all nodes need to create a candidate block. Only mining pools and those who mine solo make candidate block.
The order of the transactions in terms of block space will be different. When mining, the order of the transactions in transaction data matters. I do not understand your question. What comparison are you trying to make?
The order of the transactions in a block doesnt matter except in two cases. The first is the coinbase transaction which must be the first transaction and the dependent transactions which are considered as packages with the parent transaction verified first before the child transaction. The mining pool then pick transaction in terms of transaction fee from the of highest fee to the lowest including the packages. But this is not a protocol rule that must be obeyed because the transactions can be ordered in any way except the two cases I mentioned.
You can visually see how transactions are orgqnized in a block here
https://mempool.space/block/00000000000000000001df9394219ced52cb3789dc1c31408d6e01bec37c0b2a
They are organized by fee rate, that is basically all that matters.
There's another requirement that should be considered by miners when they place transactions in the block.
Since nodes verify transactions in the order they have been placed in the block, if there's a parent and a child and a miner wants to include both of them in the same block, the parent must be placed before the child.