I've updated the Linux packages -- the binaries within them are the same, but I hope these two problems should be fixed now. I've updated the version number, and the dependency is now on jackd rather than libjack<N>.
(I realised that removing the jack dependency from the package would require rebuilding the binary using an alternative linkage for JACK, and I'm quite keen not to alter the binary for things that should be pure packaging issues. Having a dependency on jackd seems quite common for other JACK applications, but I'm not quite sure what the "proper" way to work around this versioning problem is -- let me know if this isn't working for you.)