My proposal is based on the possibility to include part of the present concrete wall and transform it into the base of the future fence.
Therefore the proposed fence has a concrete base (if you don't like the idea of concrete, you can transfotm it into a bolder one replacing it with a rusted metal one) which on the inside of the yard is actually a planter. The rest of the fence is made out of wooden poles (painted white/grey - to go with the house paint - or their natural color). They offer a semi-pricacy to the yard and a dinamic view for the peolpe that pass it by. For more privacy I suggested medium plants to be planted behind it.
Tha mailbox is included into a conceret wall, a continuation of the fence's base.
The gates are also wooden (again painted white/gray or natural color).
In the yard I suggested using a pebbled way to the entrance with concrete slabs. In front of the house the existing planter is transformed as to create a continuous design with the fence. Also I suggested a small wall in front of the outdoor porch to offer more intimacy, plus to give a overall apealling image.
I hope you will like it!