To answer your question- no you can't simplify it down to two products unless you aren't targeting any issues.. but that still requires a cleanser, exfoliant, moisturizer and SPF protection. No point in trying to fade dark spots or even tone without protection against more damage.
first of all, The ONLY place that scrub COULD be used is for your feet.. otherwise please toss it. its terrible for your skin.
Dermalogica's daily microfoliant or their oatmeal exfoliant is literally the best thing you could do for yourself. Exfoliations (when done right) will help lighten dark spots and your vit C is great for that too... but you are missing sunscreen and a moisturizer. there are moisturizers with SPF that will be gentle and effective.
Best of luck
-Licensed Esthetician
Dermalogica's product is so expensive, is there something cheaper?
Everyone online says st Ives is bad, just Google it