Waiting a week for the herbicide is no issue, perhaps the use of said herbicide was targeted on unwanted plants only instead of broadcast spread, so replanting right away did not effect the new plants. Or that roundup was used, but roundup resistant plants were planted immediately after so there was also no effect. Or the scout showed up, and as you said the city provided all the stuff, so the scout did was the city provided, an on their schedule. Or the city changed their mind when the scout asked them about doing this project on two weekends instead of one. You do not know these details until you review, and if the city signed off, it is likely that the replacement plants didn't die due to the herbicide.
I really don't care that this is a turn key project where the scout did very little to plan.
We have things like blood drives all the time, where a scout CAN'T do anything except advertise, recruit volunteers and maybe provide snacks and thank you's, and on the day coordinate people signing in and standing in lines to do whatever the Blood Bank requires.
In lots of city projects, the city requires use of specific tools they know are safe, requires specific use of plants that they have purchased, likely at bulk huge discount, or paint or whatever other supplies the city often REQUIRES the scout use exactly what the city wants them to use and provides it and then shows up to make sure the plants are put exactly where the city wants them.
So the scout's leadership is shown in the advertising of the project, recruiting enough scouts to do the work, and then hopefully leading the scouts on what to do when thru the project itself. But everyone knows that adults OFTEN jump in to try to tell the scouts what to do and how to do it. If they were mixing and pouring cement and the adults were showing how to mix cement, you would not question that the scout who doesn't know how to mix cement should be showing how to do it, the scout would be expected to defer to the specialist. The scout then has to coordinate only the scout side, which scouts help with this part and which help with this part and who does what at clean up time. And feed and water his scout helpers and make sure safety is followed.
There are sooooo many ways the scout could have shown leadership. And even though there is a Eagle project workbook, being able to write clearly to explain everything you did to show that leadership is NOT part of the whole process. A discussion for the scout ahead of time can make it clear to him that on paper his leadership on the project doesn't shine thru, so when he shows for his EBOR perhaps he should be prepared to talk about that specifically and discuss how he overcame adult pushiness if it was happiness, or if he couldn't overcome adult pushiness (cause that has happened and doesn't reflect on the scout as much as it does on the adult)