You can easily read at Demo Page that:
demo
Limited gameplay scale.
all CG deleted
game core stay in 0700.
Demo is at version 7.7 current version is... i think 8.5 didnt rly checked and still playing on 8.3 xD But yes, a lot of stuff is gone from Demo Version... after all Demo is Demo... so answering Your questions:
- Yes, game do have more quests compared to demo
- Yes, game do have a lot more dialogues than in Demo
- Yes, You have few more places to go.
- As description says "all CG Deleted"
- Yes. since version 7.7 more Adult scenes got added and few locations got visual updates ( or im just retarded but i believe that there was no fireplace at Mama Tavern xD )