Hello Shahed,
I don't know if there is any refrence range of hb for thals in pregnancy but i personally think it may be low,thal intermedias normally do maintain hb of 7 to 8 but in pregnancy i think its low,Please wait for what Andy has to day about it.
All the vegetables and fruits you mentioned contain very very small amount of iron,on the other hand the antioxidant properties and vitamins and trace elements they offer are awesome,so i don't think your wife need to avoid any of them,and you need to learn the distinction between heme and non heme iron,iron in red meat is heme iron which is more easily absorbed in the body,so it can add to iron overload,but iron in veggies and fruits in non heme iron ,which is not that easily absorbed in body,so its not that harmful.
One more thing is when body is constantly on low hb ,it tends to absorb more iron from the gut,tea can help avoid that,please give your wife tea after every meal,that will help avoid absorbing iron from food.
I hope this helps.
Zaini.