One-way hashing the phone numbers and emails would at least be a good solution to alleviate the privacy concerns, while still allowing you connect with your friends on Path.
One-way hashing phone numbers cannot really be one way, unless you are using an inherently really slow hash function.
Without it, generating the table of say 10^10 hashes is within range of almost everyone (especially on a GPU). At say 1ms per input, it would take 10M seconds, or about 4 months.
