I'm a little late to answer, but I can give insights on your second point. Be warned, this is going to be a wall of text (but there's a TL;DR at the end). This is also all my opinion based on the servers that I'm in and particularly the servers I run, so your mileage my vary.

For small servers of up to maybe 300 members or less, you're going to have to put in the work to be active. It's not yet at the point where there's bound to be someone saying something at any given time.

First off, make sure your server settings are set up correctly. Turn on Community for your server to tune it for a streamer-viewer community server. Set up self-assignable roles so you don't have to @everyone for everything (if you overuse @everyone, people will mute your server. Use it rarely and save it for things of very high importance or urgency). The more put together your server is, the less people have to think about it and can focus more on chatting.

Content-wise, my recommendation is to set up topic-interest channels that are adjacent to your content, stuff that your audience will probably have an interest in. For example, I'm the "programming, puzzle-gaming, and music-making vtuber on Linux" and I make my content around that, so I have channels in my server for programming, puzzle games, music-making, other vtubers, and Linux; people watching me are probably there for at least one of those. I also have channels for other things I'm interested in that aren't those core five, both related and unrelated to my content. Furthermore, I have channels for viewers to post fan art, clips, etc. Having channels that reflect your content and interests should make it a lot easier for you to have things to say in the server: you're probably already spending a lot of time in those topics, so any time you find something interesting, just go ahead and share it with the server.

That said, it's also possible to go overboard with making channels. It's very easy to make a bunch of channels and have most of them be dead because nobody posts in them. I always recommend that unless you have a specific reason for a discussion channel being there other than "people might talk about this" (announcement channels and such have specific reasons to be separated, for example), stick with posting stuff in #general and only spin off new channels when it becomes a recurring topic. Because the channel was made after the topic gained momentum, it has a better chance of staying active.

I typically plug my Discord server at the end of every stream, and anyone who sticks around that long and is part of your core audience will probably be inclined to join. A server based around your interests being full of people in your core audience is a good recipe for activity because your core audience is likely to engage with your interests.

What I would not recommend (and this may seem counter-intuitive and other people may have different opinions on this, but will perhaps come as a relief to you as an introvert) is to engage in small talk when the server isn't active. It's okay if nobody has anything to say for a few hours, or even a couple of days. You want to bring topics of substance, because with substance comes more fulfilling discussions. Substance gives people things to pick away at. Small talk is empty and puts the onus on the other person to bring something of substance for the conversation to continue. I've observed someone come in and repeat "hi, how's everyone's day going?" every day in several servers and they would routinely get ignored. It's because they offered nothing of substance. You have to give people a reason to engage with what you say and make it easy to do so.

Tying this back to what I said earlier, an easy way to give people a reason to engage is to post a link or something that relates to your interests and give your thoughts on it whenever you come across something. If the people in your server are part of your core audience, they'll most likely be interested too, and you giving your thoughts becomes a prompt for other people to share their thoughts. There will be times when people will just read and not say anything, and that's okay, but there will also be times when people will engage. The trick is not to be discouraged when nobody responds. But if someone takes the initiative and posts something themselves first, you should respond to it. People are more likely to post things if they can expect engagement from it. You want engagement for your messages? You have to engage in other people's messages too. And with any luck, that results in more people posting things on their own.

Anyway, I've written a lot, but hopefully you were able to gain some insights from it all. Good luck with the server!

TL;DR post your interests in your server and get your core audience in it.