Fall Family Portrait advice

So I have my first real portrait session coming up for a family of 5. It will be outdoors to capture the beautiful fall colors and it will be around golden hour so lighting should be good. I've never done this before so I'm a little nervous, especially about poses- the 3 kids are 5yrs, 3yrs and 1.5 yrs old.

I would just like any/all advice on how to handle this. Using a T3i with the following lenses:

-Canon 85mm 1.8
-Canon 50mm 1.8
-Tokina 11-16mm 2.8
-Tokina 35mm 2.8
-Canon 55-250 4-5.6 (probably won't take this out of the bag)

Should I attempt to use flash or natural light? Recently purchased a reflector so I'll use that if needed,too.

Thanks for any comments or help you can give- just trying to prepared!

I find it easier to do more lifestyle sessions when there are multiple family members - especially young children. Have them play, sing songs, tell silly jokes, etc. You can do everything by natural light, no need for a flash, especially if you'll be outside. Best of luck to you.

Those ages won't stay still long enough for you to use a reflector! Best to just work with what the day gives you. Those little munchies move fast!

Just as April said, you'll get great photos of them not so much posing and trying to be still as you can capture while they are having real fun.