Can I use an anyday ticket to get admittance to fright fest?

Yes, but not the special haunt attractions inside.

For most of the fright fest attractions, yes. However you might require special pass for few other attractions of the fright fest

You can use to get into park, but FF is it's own ticket purchase once inside the park

I believe so. But you should call them to make sure

You can use it to get in the park but you need to purchase either a single fright fest ticket or a fright fest pass if you want to do frightfest activities

General FF as in the shows and general street performers yes. You would need a separate ticket for the specific FF haunted attractions.