OK, you said "parish" which means Louisiana and then you said "benchmarks" which
probably means Ascension. I'm a middle school teacher in Ascension parish.
Only you can judge what is best for your children, but I'm seeing a lot of "three days isn't that much", and I respectfully disagree. When I was in school, three days wasn't a lot, because we could always make up the textbook work or worksheets. However, school today is light years away from the old days. No textbooks, no worksheets, no "busy" work. With the advanced curriculum and the fast pace of instruction (due to the ridiculous number of standardized testing days, and teachers being forced to cram a 180-day curriculum into the 150 days before the LEAP test), three
consecutive days is quite a bit. Most subjects are cumulative, which means missing part of a unit may mean further difficulties down the road in future units, not just the one that we are currently on. And it's not "early in the year" - it is a full quarter in.
That being said, you know your child. If s/he picks up on things quickly and is absolutely dedicated to putting in the time/effort to
learn the missed material (not just make up the missed work), then you could make this work. Be prepared to do a lot of catch-up at home, and be aware that it will not just be a matter of filling out a few worksheets. This will be an unexcused absence (despite numerous attempts by parents to convert a Disney vacation in to an excused absence for "educational family trip"). Teachers are not required to allow students to make up work for unexcused absences. Hopefully, your child ends up with teachers who don't particularly care
why a student missed the material, just that they
master the missed material...but this will require teachers who don't mind giving up their planning periods, lunch breaks, etc. (For what it's worth, most of the teachers that I work with fall into this category, so that is a plus for you.)
I know you said your children were on honor roll, but be aware that honor roll in middle school is much more difficult that primary school. But again - you know your child best. If he is genuinely capable of learning the material on his own, you're willing to put forth the time and effort to help him catch up, then go ahead with your plans. Our students each have a Chromebook, and all teachers use BlackBoard / Google Classroom, so if you want to lessen the impact when you return home, they can try to keep up while they are at Disney.
By the way - if you are in Ascension, our grading period ends on Wednesday, 10/10, and
if (that's a big "if") we follow our usual pattern, this will mean that the benchmarks will be on the Thursday, Friday, Monday, and Tuesday before the 10th. Some subjects will be finished with instruction by the days that you will be gone, but others will still be teaching new material (which may appear on the benchmark). Also, it depends on whether your school is on a schedule that has social studies / science in alternating semesters. If that is the case then you will have an additional challenge.
And for the record - I share your frustration about the late publishing of the school calendar. We all do.