Palm trees can be dug up and gifted away, if done carefully.

If getting an apple tree, make sure it’s a “dwarf” or even “ultra dwarf” type depending on the size of your yard, or you won’t have a yard anymore, just a big ass tree.

I don’t know what’s native to your area, but for a walkable, wild lawn what works in my area, same zone in California, is self-heal (prunella vulgaris), wild violet (viola sororia), trefoil (Lotus corniculatus), with a micro clover base (trifolium repens). These all stay low, don’t mind a mow here and there, but don’t require it and are very lovely.

Because they are low growing, they won’t be able to compete with an overgrown grass lawn. Wilding the lawn isn’t really as simple as discontinuing mowing.

You can murder the lawn by cutting it short and covering with cardboard for about six months www.gardeningknowhow.com/lawn-care/kill-grass-with-cardboard Then plant what you want.

Or you can add the above mentioned plants and continue mowing as the shorties take over.

Know that pumpkins are not small plants- they will need about 50- 100 square feet per plant, but you can get mini varieties and grow them vertically, or a small “bush” variety. Zucchini is much more compact and manageable.