Frankly, your problem is too vast and took too much effort/ time, i doubt this will take less than a month to finish, thus you can’t really depend on anyone else but yourself, and the most i can offer you are some hints here and there.
First thing first, you said that this is your first time ever attempting to create AI, so may i ask you to take your time to watch some AI tutorial inside this link: A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums.
After you have firmly grasp the basics of AI implementation in your head, you may want to review how other project implemented their AI system, some example are Couch Knights and Shooter Game, you should carefully review their structure, how they interact with the environment, with player character and with each other,…
And finally, time to work on your project, but you shouldn’t start by jumping into blueprint immediately, first, try to list all kind of behaviour and attack pattern of your AI, divide them into category, such as the RandomWalking, the StationTurret,… from the data you have worked on, try to work out an AI hierarchy, with the basic AI action on the top and advace one on the below and so on. And after making sure this AI hierarchy system fit your need, that you will begin to work with the blueprint and bring life to your minions.
All of those thing above should be a challenge even to a programmer, so unless you already got a moderate amount of knowledge about programming, looking for another programmer and ask/ hire them for your project should be a good choice, unless you can spare time to learn programming, which also isn’t a bad choice.