Tokyo Alien Brothers

[Isobe-jan]

Anyone have suggestions based off of this and dedede?

You have great taste.
In terms of other similar manga, I'd of course try hirayasumi also by Shinzou Keigo. It's excellent.
If the aspect you liked the most was the slice-of-life wholesomeness I'd look into Yotsuba& (and maybe Kimi wa Houkago Insomia or Skip&Loafer although those last two also have a lot of romance).
A manga that has themes similar to dededede is Last Hero Inuyashiki, however it is much edgier and the art style is completely different (and basically the polar opposite of hirayasumi).
Bride Stories is basically Tokyo Alien Brothers but instead of aliens in Tokyo it's an englishman in Mongolia. Great art, well researched, characters are nice, good vibes.
Oh also Solanin I guess is basically the work by Inio Asano (from dededede) that comes closest to hirayasumi. It's a good read as well.

btw i'm also always open to suggestions, i'm a sucker for great art and i'm big on well-developed characters