What you need to do is give them a simple test for your own peace of mind without telling them of course and nothing intrusive or violating their privacy .
You have said that they have taken your kids to the meetings ?was that with your consent or without it ?
Do they have kids ? I dont think you have said they do.If they do say that you want to take them to a church of your choice just so they can see the difference in how people worship a God.
If they don`t have children do much of the same thing as regards your own children ,say to these people that you are going to take them to another church so that they can see the difference in how people worship a God.
You don`t actually have to do tat just make them believe that is your intention so that they get a balanced point of view.
And see what sort of a reaction you get from them , my bet it would be a negative reaction to whatever church you suggest ,try a couple if you want ,and a positive reaction to their church,KH
Red flags should spring up immediately.