This is PageFly - Free Landing Page Builder. I would love to provide my recommendations for your store based on 6 years of providing solutions for about 100.000 active Shopify merchants.
Regards your concern to add a Reorder button, i suggest you to use an 3rd apps, because that will be easier for you and to not coding anything.
There are fews app on Apps store you can choose any of them if that meet you requirements.
If you feel my answer is helpful, like it or mark it as a solution. Let me know if you have any questions.
In short, it lets your customers access their order history and 1-click add any previous order to cart again - all of these without any login or customer accounts needed. (We use a secured passwordless authentication to verify their identity)