Kindly wait for 24 hours if images are not reflecting then use Bulk Image Upload file.
Secondly, there are many reasons of not combing the listings, it may be different Part Number, Manufacture, Size map, color map Model number, etc. Both ASIN’s should have same attributions in the backend.
You will need to try by copying one listing and add other into as variations, secondly update listing by using Flat files(spreadsheets).
Can you share the flat file error when you uploaded it? If your image didn’t reflect in the PDP with manually updating it. Use flat file, partial or better full update. Sometimes you need to break the parentage just to update some child ASIN attributes. Believe it or not this worked to me many times.
Regarding the listing images update them and wait for 3-4 hours otherwise try to upload them via flat tile and it still nothing happens then straight a way open a case with support.
Secondly regarding the variation again use a flat file to create it and this issue will be fixed.
Regarding the VA question, yeah I have plenty of experience on Amazon PL and can help you to start the noon as well.