I've had quite a bit of experience with Access in a previous role as a Database Administrator & Programmer. We used Access for the front end with SQL Server back end. I had no problem with combo boxes and still to this day have built a couple of mini databases, using only access, and found that I've never forgotten what I learnt 13 years ago. Excel is confusing me. I have created combo and list boxes and managed to set it so that when a selection is made, it changes the numeric value in a separate field. I'm not going to go into explaining that, because I'll probably confuse the experts on here.
So, what I'm wanting to do is on sheet 1 have various combo boxes for the user to select the requirements. These requirements will be in various formats, numerical, text & date/times. I want those selections to populate certain areas of other worksheets, for this example I'll say sheet 2. On sheet 2, I would like an edit button which will allow them to edit the field which has been populated by the selection on sheet 1. At the same time, I would want that edit to add to the combo box list on sheet 1. I could do this is Access but not sure on Excel. Some may ask why I don't use Access. I would gladly use it and could quite possibly make it work for me, but I'm taking over the work of someone else and if I switched to Access it would cause turmoil. Plus, everyone thinks they're experts on Excel and don't have clue about Access. It would be easier, for me, to stay with Excel and when the job is done pass it over to an "expert" to look after in the future and wash my hands of it :-)