it's brilliant that this is happening. the amount of plastic that isn't biodegradable and that goes into landfill is just really quite scary. There was a program about it here in the UK just the other day, it was absolutely mind blowing and also quite terrifying at the amount of stuff that just gets buried and never breaks down.
While it is a brilliant move for the parks not to have plastic lids of straws available, i do hope they have suitable replacements/alternatives like paper straws or reusable non spill cups.
There are no replacements to the straws and lids planned. Unless you purchase your own Disney Straw or bring your own you will just be getting a cup.
Unrelated note security will now be checking for guests entering with plastic straws and lids.