Automatic discounts were recently updated to support more rules
This is either:
with the minimum quantity set ,and probably with constraint for a specific collection
Otherwise this is a product builder( aka kit selector, box builder, plan chooser,cart picker) there are many apps and customizations for those.
Yes, though you still need to setup the theme to display this list in one location.
Customziations for Quick order forms are similar to that.
I think Bold Bundles would be a perfect fit for you. You can set multiple bundles or mix and match bundles to do what you need.
We have a video here covering some of the features: https://youtu.be/_22sncF59Fc?t=35. I tagged it at the spot I thought would help you out.
I work at Bold so if you have questions just let me know!
I suggest that you can use the Upsell Cross‑Sell Smart Tool app to create upsell campaign attaching with a discount or free shipping or BOGO:
If you want to set up a discount campaign or countdown campaign, try out Discount Master app: