I was not too complicated but not having any data model made the process longer.
I still have faced an issue with my converted users not been able to view the categories. I have manually addressed the issue by creating a "legacy" group, add the necessary group/priv to my categories and manually adding my users to the legacy group (fortunatly was having no more than 150 legacy users).
I presume it has something to do with group association but haven't been able to figure out what exactly
At least 10 seconds to restart NodeBB and more 10 seconds for my plugin to load some stuff from my database and do other startups. In the case below, I simply added a space in my subscribe2.tpl and saved it.
>> File "node_modules\nodebb-plugin-myplugin\templates\subscribe2.tpl" changed.
2018-11-04T07:57:31.402Z  - info: [themes] Using theme nodebb-theme-persona
2018-11-04T07:57:32.324Z  - info: [build] Building in parallel mode
2018-11-04T07:57:32.326Z  - info: [build] templates build started
2018-11-04T07:57:33.295Z  - info: [build] templates build completed in 0.969sec
2018-11-04T07:57:33.296Z  - info: [build] Asset compilation successful. Completed in 0.97sec.
2018-11-04T07:57:34.021Z  - info: Initializing NodeBB v1.10.1 http://127.0.0.1:8081
2018-11-04T07:57:37.405Z  - warn: [upgrade/appendPluginScripts] Unable to read plugin.json for plugin `nodebb-plugin-emoji-extended`. Skipping.
2018-11-04T07:57:39.417Z  - info: [themes] Using theme nodebb-theme-persona
2018-11-04T07:57:39.920Z  - info: [plugins] Plugins OK
2018-11-04T07:57:41.873Z  - info: Routes added
2018-11-04T07:57:42.053Z  - info: NodeBB Ready
2018-11-04T07:57:42.058Z  - info: Enabling 'trust proxy'
2018-11-04T07:57:42.061Z  - info: NodeBB is now listening on: 127.0.0.1:8081