It might help us help you if we knew to which Arp family you're referring. (Did you mean to post this on the public discussions board?)
Arp is generally a Germanic surname, so it wouldn't automatically be associated with any particular Hispanic culture, but that doesn't rule it out. There is, for example, a very large German population in Guatemala and also throughout much of South America, and it's possible that someone from one of the female lines might have been Hispanic.
If you link us to specific profiles (once you get them up), hopefully we can help you out.