Secondly, even though not recommended at all, MyFamily accepts nicknames; If there's no practical way for you to automate it (such as to set up a centralized system to manage torrcs and push them to hosts), you can make a MyFamily like this:
MyFamily MyNode1,MyNode2,MyNode3,...,MyNodeN
Don't use nicknames in MyFamily. You can preemptively generate as many relay keys as you want and use their fingerprints in MyFamily so you don't have to bother about changing old configs when you add new relays as long as you use these preemptively generated keys.