Scripts can help you. Vegasaur toolkit has “Close gaps” commands that delete all empty slots (gaps) between selected events or on the current track. To delete gaps across multiple tracks you can use “Auditor” tool. Other scripting plug-ins (for example Vegas Pro Production Assistant) also contain similar tools.
Scripting API allows us to read envelope points and create other envelopes (like volume envelope for voice-over) but scripts can not change video fx parameters. They can only apply a preset.