Transactions with multiple input UTXOs and multiple output UTXOs Suppose a transaction t has 5 input UTXOs each worth 1 BTC, each unlocked by a different sending address Ai. 

The outputs of that transaction are 10 UTXOs of 0.5BTC each, each locked by a different receiving address Ao.

Is it correct to posit that each of the Ai sent 0.1 BTC to each Ao? (Lets ignore the existence of transaction fee).
I don't think you can make that assumption with any certainty. You can fairly easily invent other explanations that are equally valid (though probably much less likely)

For example, this transaction might be created by a 23292 member club with an annual subscription of 1 BTC that sends prizes of 0.5 BTC to ten winners of their monthly competition. There would be no real-world transaction that links one specific subscriber with two specific prize-winners.

The blockchain certainly doesn't assign inputs to outputs. The only requirement is that the sum of inputs cannot exceed the sum of outputs (and usually the sum of outputs is less than the sum of inputs - the difference being the mining fee)

This may be clearer if you just think of this as a record of a fiat cash transaction. If I hand out $1 banknotes to ten people, the various five people who each gave me a couple of $1 banknotes in change have no involvement in my later transaction. The sources, sizes or sequence of the inputs are not relevant.