Hi Lara, so for the upper piece you can select these 2 edges and use Construct > Blend:







For the remaining hole, unfortunately filling in that kind of smooth hole filling is difficult to do in MoI, you will probably need to use some tools that are in Rhino to help with that. I'd probably give the Patch command in Rhino a try for that, maybe after cutting away a little more surrounding area.

- Michael