ᐅ Basement Insulation, Comparing Quotes, KfW-Efficient House with Livable Basement

Hello everyone!

I have received a quote for a basement in our planned single-family home (Kfw 70 standard). For some items, I feel that some services might be priced too high. Also, I think the proposed insulation measures might be exaggerated. Here are some key details:

Building area: 100 sqm (1,076 sq ft), building shape: square, clear structural height: 2.62 m (8.6 ft)
Basement ceiling 100 sqm (1,076 sq ft) as a precast slab (thickness 18 cm (7 inches)): 8,400 €
36.5 cm (14 inch) Poroton brickwork W12: 95 € per sqm (x 101 sqm)
24 cm (9.5 inch) Poroton brickwork T18: 64 € per sqm (x 42 sqm)
Exterior wall insulation in the earth backfill area (due to slope): 6 cm (2.4 inch) drainage boards, otherwise 6 cm (2.4 inch) ETICS with mesh render. Cost: 7,200 €
Floor slab insulation: approx. 25 cm (10 inches) glass foam gravel for around 4,300 €

Is this:
1. reasonable in terms of price?
2. necessary from an energy efficiency perspective for a Kfw 70 standard?

Thanks a lot for your help!
Marcel74