I'm trying to prove that Unova and Hoenn storylines happen at the same time but it looks like many people will never believe that anyway because of current lack of official proofs. But look at it this way - it would be against common sense to make R/S remakes storyline unrelated to Unova storyline, because they all should be in the same gen. Correct me if I'm wrong but I guess that 3 gen storyline before FR/LG release was considered to be after gen 1 and 2. Point of view at games' timeline changed after some references to Hoenn in FR/LG. So it looks like that point of view will change again after some references to Unova in R/S remakes.
It's the same like people were saying that B/W "third version" will be for 3DS and didn't believe in theory that it should be still for DS. That was obviously against common sense because it's nonsense to make B/W "third version" for completely different system after all that work to make B/W for DS. Now I see that the only way to convince people to believe in common sense theories is official announcement.
Bill obviously had to make some references to Lanette's system to technically link FR/LG with R/S/E. It doesn't mean that it happened during R/S/E storyline because Lanette was working before R/S/E storyline.
Are you seriously saying that a little game design modification introduced in FR/LG and transfered to Emerald has something to do with R/S/E storyline? To be honest, it has nothing to do with R/S/E storyline.
As for Devon's researches:
So it looks like Devon's fossil reviving machine wasn't original one. In fact it's unknown which one is original because they all has been developed independently. Scientist in FR/LG says that it's "his machine", so he built it himself.
It looks like in R/S remakes Devon will make Dream World machine with help of Unova scientists, making a proof that both Unova and Hoenn are last in all games' timeline because Dream World is high-tech device which will be available only in those regions.
Honestly you cannot prove or disprove any relation between regions other than Kanto and Johto's stories because those are the only two with defined time lines.
For the Upgrade feature, I honestly can't remember if you keep normal features until Bill upgrades it later in the story or not, and depending on if so, then that does put the mechanic's creation as part of the physical story.
As for WHEN they created it, you cannot put an actual time on when the system was made. Even if it was made before the game, Lanette AND Bill created the PC system itself, not just individual systems. Lanette made her's more user friendly. Canonly, both were created around the same time by the same two people.
As for Common Sense, that only ever applies to something generally accepted by society as a whole. Crossing a busy street, common sense you'd get hit by a car. Common sense does not apply when extreme outside factors are added, Take someone from the remote parts of Africa where no technology exists and throw them into Japan, watch hilarity ensue. The person will do everything wrong if not kill many people thanks to the example chosen.
A less extreme example, Rich vs Poor, there are things a Rich person will be expected to know that poor people don't. Something commonly used in rags to riches movies, the poorer person lacks the common sense of a rich person.
Common sense cannot be applied to this discussion due to exteme factors such as Generation separation, Game Creation, General story confliction, and other things. No one would have ever said Gen 3 games were at the same time as Gen 1 if the Gen 1 wasn't remade for GBA and Gen 2 remade and referenced with time matches with Gen 4.
Though after looking at Steven's Bulbapedia page, he references Losing to Brendan/May when talking to your character outside of the Pokemon Fan Club when he is searching for the Latis'. There is a non-offical time placement depending on if you think he is really talking about Brendan/May.
An addition or expansion to Unova's region would be welcomed by myself though. I kinda want to see a new area open up where, as Cynthia says, all the current Champions meet and give you a chance to battle them.
/until the game info is out, even i am not rulling out the possibility of another older region being added on. We've been trolled and mislead before.