As a person who has been in the lifestyle since the mid 90s . . .
Take what the other couple said about the other couple with a serious grain of salt.
Finding a four way connection is really hard. Now, expecting that there be, in essence, a six way type of connection? Good luck.
Not everyone gets along with everyone. Not everyone is everyone's cup of tea. All you know is what the other couple told you. For all you know, the couple you are 'dodging' a bullet from may not like the other couple (advice givers) as well.
You are being extremely vague on expectations and preferences. Again, as someone with lots of experience, that is never wise. You do not have to treat this like you are ordering a hooker, but you should be able to have adult explicit conversations about expectations and preferences. If you wait until the last minute to do that, all you are doing is wasting your and others' time. You are building up an expectation just to have that balloon popped.
Looking at your profile, you proclaim to have a preference for soft-swap. Ok. Did you tell the other people that you ARE NOT a full swap or that it is just a preference? That is a big difference.
Good luck dipping your toes into this water. Some dip their toes and fail. Some jump in the deep end and fail. Conversely, some, regardless of how they get into stay in it and enjoy it.