I've recently been using Cladwell which generates outfits for you based on your travel capsule, but I've been happy with Stylebook too.
Re: merino - many merino items are technical looking, but work well as a layer. I have Icebreaker tees in multiple colors which take up no space in the bag but can be paired with lots of items. A black merino tee is always in my bag.
disclaimer: I am a retired technology librarian. Probably not the best person to advise on fashion...