Upstream code of LXTerminal (on git.lxde.org or GitHub) has Solarized palette built-in. This feature has been added last year, but the newer version hasn't been released for many years.
Source: I am one of the LXDE developers and I need Solarized to use LXTerminal, so actually this feature is actually dogfooding myself (?). We are currently being pushed and we are going to release a newer version in a week at the time of writing.
Update: LXTerminal 0.3.0 is released. For those who has a rolling release distros (like Arch, Debian Sid) it can be immediately available.
The background color and foreground color of Solarized palette is not correct. If you find it bothering, you can change Background color to #002b36 and Foreground color to #839496. For Solarized Light, use #fdf6e3 and #657b83 respectively. This will be fixed in the next release.
.XResourcesworks perfectly for XTerm but not for LXTerminal. – sschmeck Oct 14 '16 at 19:41