Now you are broadening the scope of your enquiry considerably. This is what is known as, ‘Project overrun’, where a consultant (in this case, UKGSer’s camping section) is asked for one thing, which the client (in this case, you) completely alters by way of the information, needs or design, after the work is well underway. This leads to considerable delays in decision making, often with significant additional costs.
You started looking for an (arguably) oversized but still lightweight tent that is suitable for a single (oversized) male, going to Iceland, outside of the deep winter, riding a motorcycle. The principle guiding factor was that it must be suitable for Iceland, as distinct from say, Norway or Greece or Norfolk.
Now it has to meet the criteria of suiting your oversized son and his girlfriend (dimensions unknown) in the Alps, which may well open up a whole different set of issues. For example, when are they going to the Alps? If it’s winter, it’s one thing; if it’s high summer, it may be quite another. Will they be seeking to camp ‘at height’ ? How will they be carrying the tent? Is the female (or indeed your son) fussy about the colour?
If I might suggest a practicable solution, please. Take your motorhome, with your motorbike on its trailer, to Iceland. You have now all but removed the need for a tent. Tell your son and girlfriend to chose their own Alpine tent.