Thursday
How do I add a note of "Please allow 2 hours" to certain categories for Toast online ordering , like for all of the 9x13 pans.
Friday
You could use the items description, or the menu groups description (under advanced settings, advanced properties). You could also use one of the the spotlight banners under branding and customization, and online ordering.
Friday
Adding a required modifier to items that have 2 hours lead time. Don't make it default so customers have to select the modifier and therefore they shall see the notice.