Short answer: possibly, but you shouldn't.
A question; if I'm using your patches for Survival, Dovahkiin Reborn and Rebalanced can I merge them? Can I merge them with other patches I've grabbed from your modular folder?
The patches from the packs are merged using the patches from the modular folder. The included txt file tells you which plugins are included in the merge. It would be easier and better to just use the patches from the modular folder. This ensures that all plugins that alters the same record are sorted in the correct order before the merge. The resulting merged plugin contains everything from the pack patch that you use as well as all other patch plugins that you may need.
Also, if nothing has changed, Merge Plugins doesn't allow you to include plugins that are merged in a new merge.