Final note on this. I hate to say it, but don't expect the server to update until sometime in August, or September at the very worst. Many many plugins are currently broken, or have some features that do not work correctly, so it makes it near impossible to get everything set up. Mojang is currently working on 1.13.1, which will fix many vanilla bugs. Once that releases, Spigot will start working on a spigot-1.13.1.jar which may or may not help to fix old plugins.
Not to mention the set-up we'll have to do once all of the plugins are fixed and stable, last time it took us about two weeks, however 95% of that time was spent building spawn and other things. Currently each required build is made and have been turned into schematics (which, are currently bugged and being fixed through cooperation on the WorldEdit github.) However, there are quite a few changes we have to make through plugin configuration as there are many more changes this time around than just plugin additions. Once again, it shouldn't take us many days to get things set up server-side (as I usually get way too excited during updates and end up working all day.)
Our update could potentially come out earlier than mid/late August, or it could come later than September. Personally I'm hoping it's not later, but it all depends on Mojang and Spigot.