1) Ali2Woo plugin has a lot of built-in hooks. Also we add new hooks when they needed. If you need some specific hook you can contact our support center.
2) Ali2Woo plugin supports WMPL and it can be translated easily.
3) As for memory, we've never got requests related with the problem from other users. If you have any problems related with memory, just contact our support center.
4) We always check how Ali2Woo works on different configurations and don't see error in our logs. Perhaps you have some conflicts with 3d-party plugins.
5) Most of the loading time of the products is taken by image loading. You can speed up this, if enable the extenal images url option.
6) "The first thing this means is that if you use external image URLs and then disable the plugin, your images are gone."
Yes, it has been done for compatibility with WooCommerce. Also you can make your own implementation of the functionality.
7) The thumbnails are supported.
8) You wrote you spent about 2 weeks to work with plugin code but you could send request to our support center. And our technical team could help you.