This is a subject of great debate so you may get some different answers. I know a lot of Muslims including locals and their definition of what is suitable clothing is definitely erring on the side of conservative but you don't have to wear an abaya and shayla - except if you are going to visit the Grand Mosque.
Unless you are staying really close to the beach you will need to alter slightly what you would normally wear. Shorts are really only suitable for ON the beach unless they are knee-length. Vest tops (or anything else that shows your armpits, cleavage or midriff) need another layer to cover up (a light cotton or linen shirt worn loose would work) or simply wear a T-shirt instead. Short sleeves are fine. Wearinig a bikini underneath is OK and the bikini is OK for on the beach. You need to dress to go to the beach cafes and not go in your bikiin. In restaurants what you are proposing to wear sounds fine - just about anything goes in hotels, but the pashmina is useful to ward off the fierce air conditioning. Also if you are travelling in a taxi you need to consider modest clothing to get to the hotel...
As for women's footwear, you will pleased to learn that you can wear anything. Flip flops and sandals are acceptable anywhere you go as a tourists/visitor. However, some places of work do not permit them and covered shoes are required.
Please read the link on the right of this page "What to wear in Abu Dhabi" for more advice.