I’m in your same situation.
I ported like 10 themes to meteor, and I think this is one of the worst part of this platform. It’s a nightmare.
There are several approaches possible:
If they don’t interact with the server, put them in the client folder and hope that they will work
If they interact with the server, check if any package exist first
If it doesn’t exist, consider creating yours, it’s not that difficult
Or use Webpack, or any kind of third party loader, to load them from the public folder. This has the bonus of speeding up your site, since loading is async and you can put the files on a CDN (you can’t do it if they reside in the client folder)
Another big pitfall is that most libraries are not reactive friendly. Latency compensation is a new concept, and it is radically different from the rest. Sometimes is better to switch to another library.
Think charts for example. Some libraries are not efficient in drawing charts, so making them reactive will put an heavy strain on the client, making the site slow. It’s better to ditch the original library, which might look good, but doesn’t work good, for a better solution.
In the past I arrived to offer 75$ per hour to find someone to help me, but nobody could. I had to learn it the hacker way, by pulling my hair. I don’t want anyone else to feel this pain so I’m writing a book on the topic, because theming for meteor is too painful, and I think that for an app having a good look is as important as being useful. PM me if you are looking for some help, I could trade it for some proofreading.
Please MDG, if you read this, consider making theming easier