Your config.json should look like this for multiple ports

{
    "url": "http://example.org",
    "secret": "your-secret-goes-here",
    "database": "mongo",
    "port": [4567, 4568, 4569],
    "mongo": {
        "host": "127.0.0.1",
        "port": "27017",
        "database": "0"
    },
    "redis": {
        "host":"127.0.0.1",
        "port":"6379",
        "database": 0
    }
}

After ./nodebb setup modify config.json remove port from url and add the port array. Then use ./nodebb start to start nodebb. It should start up 3 nodejs processes, you can check if it worked with top

You can use the search box in the category page, not all icons are shown since there are too many.

You can use any of the icons in 5.15.

Warehouse is available in FA 5.15 and 6.0 so it should be available when you use it in the ACP for category icons.

It is in the ACP at /admin/settings/uploads#profile-avatars

Previous theme detected, skipping enabling default theme What is the active theme? Can you post the output of ./nodebb plugins?

Is nodebb-theme-persona inside node_modules folder? That error means the active theme is not installed in the node_modules folder.

For deleting posts of a user something like this should work.

/* globals require, console, process */

'use strict';

const nconf = require('nconf');

nconf.file({
	file: 'config.json',
});

nconf.defaults({
	base_dir: __dirname,
	views_dir: './build/public/templates',
	upload_path: 'public/uploads',
});

const db = require('./src/database');

const uid = '123';

db.init(async (err) => {
	const meta = require('./src/meta');
	await meta.configs.init();
	if (err) {
		console.log(`NodeBB could not connect to your database. Error: ${err.message}`);
		process.exit();
	}

	await deletePosts();
	console.log('done');
	process.exit();
});

async function deletePosts() {
	const pids = await db.getSortedSetRange(`uid:${uid}:posts`, 0, -1);
	const posts = require('./src/posts');
	for (const pid of pids) {
		await posts.delete(pid, 1);
	}
}

Replace the value of uid with the target user.

Spiders wouldn't see deleted post content unless the spider group is given the view deleted privilege.

You can use the custom css section in the ACP to customize it, just give the navigation items a custom class in the class field. Then use css to target that.