how to instantiate a prefab that resides on a web server

Questions & Answers
1

Do you have to have Unity Pro to instantiate a prefab from a web server during gameplay?

(That way all your prefabs don’t have to be in the “Resources” folder of the build.

Specifically, do you just put a .unitypackage on a web server, then get the prefab from it, and instantiate?

2

Not a “.unitypackage”. You have to create an Assetbundle. This can only be done if you have Unity pro and only with the scripting API (BuildPipeline.BuildAssetBundle) in the editor.

There are some scripts on the UnifyCommunity Wiki that can help you to create assetbundles on-the-fly.