question Two associated domains and projects parked at 2 seperate registers. Linking the theme

[Greenly]

Recently, on a bit of a whim, I purchased a .ai that I thought had potential. My reasoning was that it fit in a niche and sounded good to me. Here's the rub, it's too specific and requires an explanation which doesn't work out so great for...well anything. It was too expensive to register to just drop. So, I doubled down, bought the . Com version and proceeded to start a project page with that. It's coming along.
This morning I had an epiphany over my first cup of coffee, and decided to develop the . Ai domain as an anthology of fiction that parallels what I'm posting on the . Com. Then link them together as an interesting package.
So here's my question, I know it took a minute, I registered the domains on 2 different platforms. The . Com I listed with WordPress because I could build a free page, and pay later, and the . Ai on godaddy. Should I move them to the same server? And which server would allow free web pages, to later upgrade, with the least amount of drama. I'm also new to website development. I used web press a decade ago. Things have changed
Thanks in advance

 

[Greenly]

Well, I'm working with WordPress as it looks like the simplest for a newbie such as myself. So much to learn.
I really do appreciate all of the professionals who are so generous with their knowledge. It's a gift you share and I thank you
Cheers!