I didn't know crabapple trees got that big! From the looks of the trunk it must be huge.

I can definitely help with suggestions, but I'd really need a better idea of how much--how many hours--of sun you get in the specific places you want to plant (and direct or "filtered"). The only way to figure that out is to take a day when it's sunny and go out and check about once an hour. Mark specific places you want to plant and then make brief notes when you check.

But before you plant too much I think you need to figure out why things like hosta and heuchera--and strawberries aren't growing there for you. Whatever is keeping you from growing those things there could keep you from growing anything else there too, so no point in spending money on more plants till you solve that mystery. When you had those plants, how often and for how long were you watering? Are there any other factors you can think of that could have caused a problem with them? All three of those things should be pretty easy to grow.

You said "had" lilies. Did they go away/die on you, or did you move them?

Creeping Jenny can be grown as a water plant, so I'm not surprised that didn't make it. That stuff LOVES to stay wet all the time.

Have you not had any problem with the Euonymus spreading/flopping all over the place?

Have you successfully grown anything in the big pot?

You haven't been around here long enough to know this yet, BUT, I very often start out with a whole lot of questions to help me--and others--give a useful answer to whatever has been asked!

I can think of several things to possibly suggest when I have more info,
Skybird

My "near crab" is enormous. I am lousy with math, but would say that the canopy is at least 15' in diameter, and I prune it back every year.

I can answer a few of the other questions now. The amount of sunlight obviously changes with the season, with more in the spring. I'm always sad when it gets shady enough that the color in my Rosy Berberis fades. :( Right now, that area gets nearly full sun until afternoon, but the crab hasn't bloomed, much less leafed out.

I'm not sure about why I lost my Fragaria; it was going strong for a number of years, then disappeared within a single season. I was just looking at my 2011 journal, and that was the year that they simply disappeared. The Creeping Jenny has held out longer, and is coming up now in isolated patches. I had been under the impression that the Creeping Jenny liked to be dry. I have a drip system with individual emitters, so I can play with how much water I give to a given area by repositioning them or changing the length of a given zone. But that is just as of last year. I was not great at watering regularly when it meant an entire day of timing and moving the hose around to my soaker hoses. It will be much easier now that I can do it automatically. :)

I must not have been clear about the Hostas; I do not care for them. I do like Heuchara, and had a beautiful purple one (I think the variety may have been Plum Purple, but would have to check my old notes. It simply failed to come back. I tried the Firefly, which I particularly like, but it did not thrive either. I honestly cannot say how much I was watering at the time; it was back when I was just beginning. My Jack Frost Brunnera is coming back nicely from the freeze, and is actually throwing a baby. I know that the plain green ones do that, but did not think that these did. I'm pleased.

With regard to my lilies, all but a few have been Asiatics. The few singles that I got from B&D just faded out. They were Asiatics and in the drier area of the garden. I am partly convinced that they did not get enough sun. The other ones (Crimson Pixi) (in picture below) that I had did beautifully, but I think that I let them get too crowded. I was hesitant to divide them, and started getting fewer and fewer each year. I kept vowing to divide them and never did. I plan to replace them this year and be better about that. I had some Freya in the shade because their brilliant yellow died out quickly in the full sun and the B&D folks suggested that I give them more shade. They also did beautifully for a while, but may need dividing as well. The other possibility is fertilization. That may be a problem throughout my garden; I dug an amazing amount of compost into the soil (down to about 4'!), but have not fertilized since. I keep meaning to...

The pot is there for purely decorative purposes, and is filled with rocks and topped with colored marbles.

The Euonymous is indeed spreading and flopping. I plan to cut it back this year - should I do it now?

I don't know what else to tell you. I will make a point one day when I am home all day to photograph the area that I want to plant at 2 hour intervals all day. I did that when we first planted the garden, but haven't done it since, and the crab has really spread since then.

Skybird's never-say-die yellow columbine would probably do well, she might be able to tell you what kind it is. It does like to self-sow, though. Bigroot geranium seems to take anything you can throw at it and spreads by runners - slowly - and is very easy to control. It does beautifully under my apple tree where it's in dark shade all morning and blazing sun all afternoon. I have a neighbor who has it under a huge oak in part/full shade all day and it does great there too. I can pot some of either or both up for you if you're coming to the swap.

I know you'll get lots of great suggestions here, good luck!

I'd love either or both! Thanks!