I have no idea about her personality and if she is high maintenance or not but I find the avocado BI very hard to believe. Wasn't Suits filmed in Canada? The climate there is also not good for growing avocados and she survived. It's not like she's never lived without avocados and I find it hard to believe she couldn't get them at least occasionally with all the money she has.
I do wonder if she's having some second thoughts related to the viciousness of the press. Unlike Kate, she wasn't under their scrutiny for very long before getting married and may not have been prepared enough. She had some exposure being an actress but she wasn't even an A-lister and even the biggest movie stars, as intrusive and vicious as the press can be towards them, don't have it as bad as someone who marries into the royal family.