On Amazon a configurable product is called a variation listing. Depending on the category you’re in, you can vary the products by different attributes, but most common is by colour or colour & size. I can’t say for certain because I don’t know your specific category, but I don’t think you’ll be able to vary the products by those attributes you’ve mentioned - but the workaround is vary by the ones Amazon accepts, and for the names of each attribute you can decide yourself.
For example, if you decide to vary by colour & size on Amazon, you could write this:
Colour attribute: Green
Size attribute: 5m
So to the customers it shows as being varied by colour and length, but on the spreadsheet it’s varied by colour and size.
It will be quite complicated for all these - outside of the clothing category I’ve only seen a variation listing have 2 options on it (size & colour normally), so I would recommend splitting the listing already.
Each possible product in the variation has to be a separate SKU and EAN (1 barrier, 5m long, in green, with wall terminator would be one product, then 1 barrier, 5m long, in green, without wall terminator would be another, separate product). From what you’ve said, it sounds like this is possible for you.
You can create these variations manually, through the ‘variation’ wizard, but personally I prefer to use the spreadsheet uploads to do it. You need to download a category-specific spreadsheet for this from here:
Inventory -> Add products via upload -> Download an inventory file -> (select your category) -> since you’re listing these products from scratch, I would recommend the ‘advanced’ mode -> generate template
There are different tabs in the spreadsheet to show which attributes are acceptable for each column (some you can put anything, others are fixed). The spreadsheet also tells you which information is necessary, and which is optional. If you’re creating these products from scratch, you should fill in as much information as possible (that’s relevant to the product).
Hope this helps, and that it makes sense!