Hi!
What a gorgeous pair! But I am a bit prejuduced, having such fond memories of my own white aby Bethan and gentle golden smooth/American Hafina!
As to their favourite veg:
Cucumbers are usually part of a daily diet, the others should not be fed daily.
Strawberry greens and dandelions are OK, but they are middling high in calcium if fed on a daily basis. Parsley is even higher in calcium; try and see whether cilantro/coriander is as welcome as that is less high in calcium and fine to give a sprig daily. Carrots are too fattening and sugary to be fed daily - they are the equivalent of a burger with all trimmings. And piggies are suckers for junk food that is high in sugar and fat as much as we humans, so best stay away from that!
Fruit (tomato is also a fruit) should only be fed max. twice a week in small quantities as the acidity in it can cause lip infection when bugs (bacteria, fungal or nastier things) get into the tiny cracks in the skin that come from feeding fruit too much and or too often. If it catches one of the nasties, it can be deadly for the piggy. Not worth the risk!

Here is our guide what you can feed how often and in what quantities:
Long Term Balanced General And Special Needs Guinea Pig Diets
Edible And Forbidden Veg And Fruit List With Vitamin C Grading
I would recommend to use favourites less as part of a daily diet but as treats to make friends with them and to lure them into a carrier, have them come to you etc. That is fine as long as yor do not overdo it in terms of amounts and keep counting your treat veg as part of the daily veg diet - i.e. don't feed coriander when you feed parsley etc. and use carrot in very small pieces to go further on those days you use it.