Will the left hand side truly not have any ground up next to it? How long will the retaining wall need to be and what will it eventually die into? What direction does this face? How will this level be used?

We have a partial walk out basement where one side just has exposed daylight windows and then the lot falls away so the other side of the house is a full walkout. Our short (3 ft tall) retaining wall is only 8 foot long and tapers down to the ground at the end.

Also consider how elevating the house 2 feet changes things in the front. Are you in a subdivision or how wide is your lot and how does the fill affect the front yard? Also while we are only 2 steps up into the front of the house, we are 5 steps at the garage side. I was sick last year and let me tell you, those steps were a problem. How old are you are how long do you plan to stay in the house? Are the steps a potential issue or no? We also have 9 ft ceilings in the basement so that also raised us up.

Some things to think about that aren't just $$.

How did the house get designed with a walkout basement with a site like you have?

It appears that the drawing suggests 8' fall ... and you only have 2'.

Typically the way math works out is:

If you choose basement let's say 9ft stem wall - it will give you 8'-7" finished basement height because of 4" slab and the drywall . 10' stem walls will give you somewhere 9'-7" finished height.

You stem wall suppose to be a minimum 8" above the grade. But most builders will do 10"-12" minimum because they are not crazy enough to risk. So your first floor now will be 12" + Joists + 1.5" mud sill. Or already 2' above the ground. This gives your basement only one ft above the ground. So with 9' stem you need to drop another 8'.

The rest depends on how deep is your house. If your house is 60' deep , dropping 8' that is only 7 degree slope no big deal, but 15' deep and when the drop is 8' and pretty steep.

If you plan to raise additional 2' or make your front door 4' from the elevation - that could help with reducing excavation but also will lift your house....

3 things could happen when you fight that much with the existing topography:

1. You will have an awkward first floor height and your house will look too tall from every angle.
2. You will move enough dirt to put in your basement, and use retaining walls to isolate your home from the existing (true) topography
3. You will move a TON of dirt and work to alter the topography making it look the that was the original slope, with using some retaining walls, but still continue to contour and adjust outside the retaining walls for full integration and making it look like the placement and grading was natural and intentional

These options are in creasing cost order.....

Also I am sure your grader will tell you that, you do not want to step foundation from a corner of your house. You will have some exposed concrete with damp proofing. You want to have some flat section before it will start to slope....

Redesign the house as a two story. The site is not suited to a basement of any variety unless you want the traditional short, dark, and creepy kind. And that’s only if the frost line is deep. Otherwise 2’ is nothing for a slab foundation to overcome. It IS for any type of usable basement with egress.

So, who ran off and designed a house without a site survey? That’s like Step 1 in Designing to the Actual Site. Which is always Step 1 in any custom design. It avoids the Plopped House Syndrome, which you’re trying to fix right now. An issue that never had to happen.

I'll agree it's time for a rethink. Strive for a cohesive design the works with your building site.

https://www.houzz.com/discussions/5918028/side-elevation-and-basement-layout