Hey catch,
Congrats on the new house, you must be proud and excited! Have your open house, please do

It will relieve some of the confidence issues about why people would like you. It will be a situation with a purpose and you wont need to worry about what to say etc... their there to mingle and see the home, just give yourself some practice tours and I am sure it will go great!
I also find allot of what you say to be very close to myself and my feelings, except I think I am just more content with it. I can count on my hands how many friends I have and 8 out of 10 are friends simply by association. But I am ok with that

Not many people in their 20's want to hang around sober talking about business, history and art, and thats ok. Allot of friendships are just that, common grounds, friends by common interests. Have you ever sought out a social network based around what your passionate about, lats say its boats, look for a boat club, or a mustang club etc... anything that you feel confident about and will have/host activities that you and others can share.
Hope the home treats you well
0ldsoul