he only has to include it with higher fees
Should use equal fee fee rate, if the purpose is both transactions are included in the same block.
The both transactions being confirmed the same time is possible though the chances are also thin
Why do you think the chance is thin?
If the bot broadcasts the second transaction once it sees the first one and the fee rate used for the transactions are equal, there's a very big chance that both transactions will be included in the same block.