Why should drainage be done at all 4 corners of the house? One side is sufficient; in this case, I assume the gable sides are on the right and left, right? Then I would equip the left side with downspouts, please not on the right, as the garage will presumably be there, and as few pipes as possible should be laid beneath buildings. I would forgo the inspection chambers, at least in the area of the rainwater; if there is really ever a problem, it can be excavated and repaired given the shallow depth. Unless they are required in the development plan. The depth should be 0.80 m (frost-free). I would also recommend choosing DN 125 or DN 150 for the rainwater; the additional cost is low, and the pipe is adequately sized for heavy rain events. For wastewater, I would also go with DN 125 in the outdoor area.