But, on these summer fill deals, when you contract the tons to CF or Koch, do retailers/wholesalers have to wire the money to lock in those ton commitments? 
Fill was pay when pulled. Term was prompt-Sept. Fall prepay is 25% down at beginning with 75% due Sept

Does the record tonnage booked “mean” anything in your eyes? Are folks sitting with lots of liquid cash right now to lock/buy the summer fill tons? 
Yes on the record booking meaning something. The large retailers see the ability to set their average fall term costs for their average.
Not many at farm level standing in line yet. But retailers need it to average their costs. 

Is it a pre-emotive hedge against input inflation or fear of greater input inflation (transport costs/nat gas price rises) because of Iran conflict? Is there more to worry about the global nitrogen impacts because the Middle East ammonia plants will always be convenient targets? 
I think taking possession and filling is a good hedge at this point. Transportation costs will start to ease when fuel lowers but I don’t think it will be in time to move fill tons. Their are trucks standing in line to move this that are looking to work after a slow spring season. 
India is done with their Urea tenders so that market is within $10/ton of last year now. 

The opening of the Strait
Allows sulfur exports to resume which should be bearish its price (1 of the 2 major variable cost inputs for phosphate production)
Allows NH3 exports to resume which should be bearish its price (the other major variable cost input for phosphate production)
Allows Saudi Arabian finished phosphate goods to export which should be bearish the market