Pine floorboards - wax, oil, stain, paint?

[KMcC]

Hello

I have a job ahead of me, we have just stripped carpets out of our house to uncover our lovely pine floorboards. Still need to sand the down so question 1 is

1. Will the black border stain probably come off when sanded?

Then I have two plans, downstairs I would like to keep the boards wood coloured

2. so what is the best product to use for pine?

Upstairs and on the stairs if the sanding is successful at removing the dark stains, I would like to have a light blue/grey sort of colour, a bit whitewash style or perhaps light duck egg colour but still want to be able to see the wood grain

3. What product would I need for this? Any ideas where would see it?

Thank you in advance
K