1. There is an add-on called easy populate that will import a spreadsheet version into the database. You can also try apsona shop manager which will do the same thing a bit more easily. There are also commercial shop managers out there that are not free that have enhanced functionality.
I'm familiar with EP, I have it on my OSC site and it is NOT user friendly or easy to use. I don't want it on my new Zen cart.
I have custom scripts that I had written for me in OSC that I would want to port over to Zen
2. Coupons have a fixed amount or a percentage discount. If they are fixed amount a person can use up to that amount so that is effectively maximum spend. You can read
https://www.zen-cart.com/tutorials/i...hp?article=336
Ok, that is satisfactory
3. No they won't. You'd need to get them 'translated'. Usually, this is not a huge issue because the structure of Os and Zen is still quite similar but it would involve some coding skills. Many of the main modules have already been adapted for Zen or replaced with alternatives. Have a look through the 'Free Software Addons' to see if what you need is there.
I would want my scripts recoded for use with Zen
Finally, I'd just install a version of Zen so that you can have a play with it. It is pretty quick easy and free to do.