Juice fasting...i have a couple of questions...

If your hand held is powerful enough, you can. Most are not powerful enough. Try it out before you start then you will know. You want it liquified, no chunks.
BTW-Using a blender creates a smoothie, not a juice. Juice is different, for that you do need a juicer.

Smoothie- full fruit/veggie blended up. It has fiber. It will have all the same nutrients as juice, just won't hit your blood stream as fast (as in sugars), and takes longer to digest.
Juice- made with a juicer, extracts the fiber, you get the same nutrients, but in a more liquid form. You get more nutrients with juice, as you typically drink more.

I've done the fast with both. I prefer the juicer as kale fiber can be a little nasty in a smoothie. Plus I like the flavor of a mixed veggie juice better.

What you use depends on what you are trying to achieve.
-if this is purely for weight loss, and not due to health issues- which means you don't need as many nutrients, a smoothie is fine, and you will find the fiber will keep you fuller longer. You will consume less fruits/veggies with a smoothie than with a juice, as the fiber ads bulk which results in more smoothie texture (it's way thicker!)

-if this is for health issues- and you need a lot of nutrients, such as a nutrient deficiency, cancer (Gerson therapy), etc, you would want to use a juicer. you get more servings per ounce, and more nutrients, but you have to drink more because of the lack of fiber.

My favorite way that I did this:
I did a (juicer) juice in the AM, then raw fruits and veggies for lunch and dinner (and only those- no oil, meat, carb, sugar, salt, etc). Once you get past the first 4 days, it gets better. the first four days are the toughest. This was the easiest to stick to, as psychologically I felt fed. I did this for 15 days that converted to the eat to live diet for a further 6 weeks, it totally got rid my cravings. Note- I did do the full juice fast before, the second time is when I did this, and it worked better.
Now I just do a juice in the am, a clean diet (mostly eat to live- but with eggs and yogurt) and I use smoothies for protein powder days, when I'm doing weights.


As for freezing, you can, but juice and smoothies oxidize when exposed to the air, so the nutrient content changes within 24 hours. So they are not nutritionally the same the longer they sit. I just make mine fresh every day. When I juiced for multiple meals, I made two batches per day. Even in the fridge within 24 hours they would look and taste different than when freshly made. I personally would not keep them in the freezer unless they were in an airtight pouch that was vacuum sealed. It doesn't take that long to make them each day.