We are thinking Spike might be a Basenji Terrier mix. He definitely has the basenji personality and the bark. We love him no matter what he is but we are curious.
I can see why someone would think there was Terrier, but I'm not so sure about Basenji. (The only way to know for sure is to do a DNA test.) Both of your dogs look very similar. What breed, or mix, is the older one?
She is beautiful! All dogs are lovely but basenjis do tend to grab those heart strings. I hope you can find some answers, it’s so hard to miss them so much!
The traits you described are also found in most of the Nordic/spitz type dogs. I don't see anything overly basenji-ish about him in the pics. What ever he is, he's very hansome.
Look at the BRAT mixes:
http://basenjirescue.org/DOGS-MIXES/Default.htm
Check out Tia. I think that's what you are looking for. :)
Then look at Tyson and Shiloh. Not the right coloring, but similar build and coat….