Stain removal

I have a large deck that, i believe, the previous owner pout a semi-transparent stain on it. The wood was very dry and splintering in spots. We first pressure washed it. We decided to replace some boards with new pressure treated boards. After that the entire deck was sanded with an orbital sander. The older boards still have some of the old stain coloring which actually doesn't look bad. We thought, however that we should try to match or go a little darker to try to blend in the old and new boards. In hindsight we should have tested very small inconspicous areas. We applied stain to about a 3ft by 10ft and to another 2ft x2ft spot to see if we liked the color. Well, we don't.

Questions:
1. What is the best way to remove the stain we applied? Wll we need to use a deck brightener on those areas after removing the stain.

Slightly different topic:
2. Should we have applied stain remover to the entire deck before we sanded? Did we skip a crucial step?
3. Should we apply a deck brightener?
4. We've decided we want to have a more natural wood look. Should we still try to put a semi or transparent stain on it or just go with a sealant? And oil or water sealant? I'm leaning towards an oil sealant.

I understand this is a lot of questions so any advice will be greatly appreciated.

Thanks!

Deckowner