I have firstnamelastna.me. Can you get a little creative with the TLDs?
To answer your question tho hello@firstname.com would look better than Lastname@firstname.tld
You can also do a catch all and use anything@firstname.com (eg google@firstname.com) but those get a little spam happy.
Linux has directories (folders) that contain programs. The two major conventions are /bin (short for binary which is another name for an executable program) and sbin (system/super user binaries).
Kbin seems like a play off of that, don’t know what the k implies tho.