A lot of these seem similar to Tokyo DisneySea lands. Italia is like Mediterranean Harbor, Fantasy Gardens is similar to Fantasy Springs, and American City is similar to American Waterfront. Do those existing lands fail to deliver what you're looking for in some way?
Agrabah is similar to Arabian Coast, but you could just switch out the Sinbad ride for an Aladdin dark ride in which guests ride a flying carpet through his adventures. This is one attraction where I wouldn't mind experiencing the scenes from the movie, since flying through the Cave of Wonders, Friend Like Me, Prince Ali, and a Whole New World would all be very compelling.
Mysterious Jungle seems a lot like Adventureland, with a more particular focus on Africa. You could obviously use the Jungle Cruise, but if you wanted something new, a river rafting ride down the Congo would be a possibility (they have that at Busch Gardens Tampa). Another water attraction might be based on the mighty Victoria Falls. Tarzan is set in an African jungle, so you could include the Tarzan show from Shanghai Disneyland or develop a wholly new attraction.
I developed a Silicon Valley land for my own version of California Adventure, and it seems quite similar to your Digital Frontier idea, although it has nothing to do with the SEA. (By the way, in my mock-up of Tokyo DisneySky I included a Cyberspace land based on Silicon Valley, so I do think it would fit in other parks.) I imagined Silicon Valley entirely indoors and sunken, as though you've entered the technology undergirding the other lands. Some potential attractions:
1) Tron Lightcycle Run. This attraction from Shanghai Disneyland fits the theme well, although I wish they could mount the lightcycles on a rotating base, to simulate that sharp cornering effect you see in the movie. If you want an original thrill ride, I had also considered an attraction called Information Superhighway that would take you on a high speed journey of an electron or data packet through the Internet, but when Tron opened in Shanghai, I decided to use Tron for the high-speed attraction and make Information Superhighway a slower moving attraction (see below).
2) Information Superhighway (a.k.a. the Data Mover). A ride similar to the People Mover in which you ride a "data packet" through the land, and secretly learn a bit about how the Internet works. Watch out for the Firewall!
3) Ralph Saves the Internet. An interactive shooter ride, in which Ralph and Vanellope have been tasked with wrecking the dangerous denizens of the Internet. You'll take on viruses, worms, bugs, spam, spyware, software pirates, phishing, Trojan Horses, and Internet Trolls. You could have different types of games or challenges associated with each. For example, you could play a Hogan's Alley type game where you try to shoot Spam but not legitimate e-mail, try to shoot worms before they divide and propagate, try to predict where Spyware will appear, and so forth. Using digital screens does fit the theme here, but some practical effects as you transition between screens would be ideal. Your ride vehicle could look like the glass vehicles from Ralph Breaks the Internet.
(Some backstory: Originally I had included an Adventures Thru Cyberspace ride as a counterpart to the old Adventures Thru Inner Space attraction at Disneyland, but then I noticed that so many of the distinctive terms of Cyberspace could make interesting enemies in an interactive shooting attraction, so the idea morphed into the shooting attraction Defenders of Cyberspace. Then when Wreck-It Ralph 2 came out, it occurred to me that it might be preferable to theme the shooting attraction to Wreck-It Ralph since it has a video game feel. That said, maybe you'd prefer to have a Wreck-It Ralph attraction separate from the shooting attraction, in which case you could use the Defenders of Cyberspace idea).
4) Baymax Reprogrammed. An attraction somewhat similar to Stitch Encounter where we meet Baymax and have the opportunity to use touch pads to vote on new chips that we'll use to reprogram him. We see Baymax humorously try out his new programming.
5) Hyper Disc. A spinner in the dark, sort of a Space Mountain for flat rides. You enter the disc and the doors close you in. You can see a vertical laser beam (maybe just on the wall) that seems to be motionless at first, but as your start rotating it also secretly starts rotating in the opposite direction to give the impression that you're going faster than you actually are. You also have air blowing to heighten your sense of speed as you rotate.
Dining:
1) Digital Diner. This serves typical theme park fare, but with the twist that absolutely everything is square. Square burgers, square pizza, square fruit cubes, square jello cubes, square cups for drinks, you get the picture.
2) Bits and Bites. A snack stand that sells cookies and applets.
3) Internet Cafe. Get your java here.
