Can I use the units out of order?
The short answer is yes! Just use prudence. The units are best taught in the order in which they have been laid out in the scope and sequence to align with the natural growth of writing that occurs throughout the year. However, there's a lot of flexibility built in, so it's fine to shift the units a bit as needed to align with your district's pacing or other content areas.
We have a lot of teachers that start the program mid-year. Some teachers still prefer to start with the first monthly unit, even if they are starting mid-year, especially if their students are especially new to having a consistent writing block. However, some teachers may have already taught the first genres like Personal Narrative, so it's best to choose a writing type that hasn't been taught yet, or one that students may need more support with. The Informational or Opinion units are great to start with too.