I can see how this would look confusing and logically incoherent, but the reason that 5 statements, each about "something alone" can co-exist is that each of them achieves something different "alone". This can make more sense to look at, by chaining three of them together, as per the first line of the summary of "Faith alone" here.
Justification is by grace alone through faith alone because of Christ alone
"Grace" and "Faith" are by far the easiest two to get confused about here, but in essence each of these "alones" is accomplishing a different thing:
Grace alone: God's grace is the means by which we are justified - not exemplary behaviour
Faith alone: Faith is the means by which we access Grace - not through empty religion (but this doesn't mean that somebody more "religious" than you is guilty of "empty religion" by default)
Christ alone: Christ is the one through whom this is accomplished - not any other saviour / sacrifice
The other two are much easier to distinguish because they don't directly have anything to do with salvation.
- Scripture alone: Scripture is the only ultimate authority on Christian teaching - not the church and more specifically for the reformation, not the Pope.
Interestingly though there was a lot of difference on this point between different parts of the reformation, on exactly how much "Catholic tradition" they were going to keep, and how important tradition and authority are- generally the consensus was that scripture was always the ultimate authority, rather than having a human authority on roughly the same level.
- Glory to God alone: God should be our highest priority and is the only one worthy of worship
This is a different point to the rest as it doesn't deal with salvation, or authority with regards to teaching. It is a statement about God's ultimate goodness and worthiness in a sense that is "other" to anything else.
