Lodging near Lilla Essingen?

My first thought is why are you planning to stay in that area? It is not a part of Stockholm I'd recommend for a visitor. But if that is what you are looking for, there is a hotel at Lindhagensplan, within walking distance or Lilla Essingen.

I have relatives nearby and we stay at the Courtyard Marriott (between Thorildsplan and Fridhemsplan subway stations) which is just about in your preferred area. Obviously it is a chain hotel, so not much character, but it's fairly reasonably priced and very convenient to public transport. There's a bus stop there too that would offer a 5-minute connection to Lilla Essingen or I think you could walk in 15-20 mins.
Badger, maybe this is the one you mean?

Probably, between Thorildsplan and Fridhemsplan sounds very much like Lindhagensplan.

The plan is to visit relatives who live on Gjorwellsgatan, so was hoping to find lodgings (and some good restaurants?) near them.
I appreciate the group's help!

Looks like the Courtyard hotel I mentioned is basically at one end of Gjörwellsgatan, so would probably work well for you.
I don't know too much about restaurants in this area, as we normally eat at my relatives' home or go out in other parts of Stockholm. There are some good places in nearby Kungsholmen.
Not sure when you are going on this trip, but the Mälarpaviljongen right on the water is nice (but only in the summer, open until end of September) - about 15 mins walk from the Courtyard or you can take a bus. https://ny.malarpaviljongen.se/en/

Then it seems like a good option for you. There are a number of restaurants in the area, although I can't comment on them as I rarely visit those parts of Stockholm.