No Tzippi in this case you would just say Family X are a very frum, warm, homey etc family because in this instance the word heimish is wrong. When asked what is their background then you answer as appropriate.
I get asked a great deal for information and advice on shidduchim, dating etc and I always say choose your words carefully because someone is listening very carefully to what you’re saying and you must be accountable for the exact words you use when giving info for shidduchim.
Hope this helps you a bit more