Purchased a high lift blonde..Can I use?

I can't say whether it's advisable to use that dye, you might be better with a colour remover first, but regardless I'd wait until after the haircut.  Why waste time and product on hair that's going to be chopped off the next day?
See what you're left with and figure out from there what's required.

My hair isn't that long, so little product waste, and if I fry areas she can cut them up. Anyhow.. Cut two test strands off. One in bleach the other in high lift, neither lifted a lot , but the bleach way more. So then on to the second part... Will the satin HLA 12. Work as a toner? Isn't a toner a dye to just tone down the highlighted areas? Or should I use the wella violet base I have ( very light blonde) with a 10 or dilute as a 5?

If you are going from shoulder length to a pixie cut, and have grown out roots, after your cut the majority of the hair will be virgin. So I agree with Kitebunny, better to dye after the cut, and if there is a lot of old dye left take it out with a colour remover before resorting to 40 vol bleach.
Tint won't lift tint, but the dye you have bought will probably give enough lift on virgin hair (although without a photo I am just guessing)
I wouldn't use a high lift blonde as a toner, especially on newly bleached hair. I would use a non oxidative toner personally, but if you are determined to use an oxidative toner choose one that is designed to be deposit only with a very low vol peroxide.
If you have used a colour remover to take out the warm strawberry blonde tones it shouldn't be so difficult to put some cooler tones in after lightening, especially as your base is already dark blonde/light brown. A direct dye like Pravana silver is a very gentle yet effective option. It will only give a true silver on very light blonde hair, but will tone darker/warmer blondes to an ashy cool shade.

Definitely dye after, if you're not doing an all over colour. Placement can look terrible on short hair when it looked fab on longer.

Thanks... My appointment is later today... We will see how it goes.. Then I will work on my silvery highlights... I'll let us know!