Any replacements are a start. As time goes on, you'll find a replacement for your replacement and update the horn again.
Before removing any assets referenced in the config.txt, you need to check what it is. The horn for example is something that is easily found. The other asset may be replaceable or if not and may end up being something that's needed to make the asset work.
If you do decide to remove the asset from the config.txt, you need to remove the kuid not only the tags and containers, but you also need to remove them from the kuid-table, otherwise the asset will still be referenced.