Manufacturing reinforcement for concrete columns

Hello construction professionals,

I want to set smooth concrete columns as property boundaries, between which I will build walls. The concrete columns should have a cross-section of 40 x 40 and be 235 cm long, with 80 cm embedded in the ground. We want to set the columns with an excavator after production. For this, they will be fixed from all four sides with a concrete bomb, and later concrete will be poured between the columns. The strip foundation will then be built upon. Finally, the C50 should be painted with a 2K paint, as we live on a federal road where a lot of salt is used in winter.

Can someone make me a sketch of how to best reinforce the columns? So that I can still properly compact with the needle vibrator (30 mm needle diameter) and remove all bubbles from the visible surfaces. The entire wall structure is freestanding, meaning it does not have to bear any extraordinary forces.

How is the connection between the fully concreted columns and the strip foundation supposed to look? Normally, the strip foundation would be concreted first with connecting reinforcement for the columns. Then the columns would be formed on the foundation. Since the columns practically do not have to carry any load, I would place 4x 12mm bars in the corners of a bent cage, outer dimensions 25x25cm. Of course, I am not a structural engineer! If you concreted the columns first, special connection reinforcement would have to be installed there, which must be bent out after concreting.