Bill and Ted (film)/WMG

Rufus is not his original name.
As many often point out; Bill and Ted only learn Rufus's name from their future selves; who heard it from their future selves; etc. The name comes out of nowhere. However, in order to keep the timeline that he wants to create; and because it's rather an honor to be given a name by "the Two Great Ones'', he went Sure Let's Go With That.
 * Also, quite a bit of Smiling And Nodding is required with Time Travel; to avoid Paradox.

The "perfect" future society is, in fact, a totalitarian police state ruled by an insane cult.
We see very little of it, but what we do see involves a lot of people dressed identically, sharing ritualistic chants and gestures, and of course, worshipping a rock band as their gods. Rufus, who clearly buys heart and soul into the party line, points out there are no wars and no poverty, but beyond that all he can say is everything's very clean and there's been an improvement in bowling averages and mini-golf scores -- sounds ominously like a society that's proud of how they've achieved "perfect order". The statement that a band's music has aligned the planets and brought all species into harmony sounds very much like revisionist propoganda. Is this possibly just an obsessed fan club gone way too far?
 * No, it's more like the planet Vulcan, where everybody achieved a higher level intelligence and culture. Ask them, they'll tell you.
 * Oh, thank Anthy, it's not just me!
 * This must be some relative to Godwin's Law of Time Travel. The state took over because they went back.

Bill and Ted are spanners from Continuum.
And they have Rufus' Spanbook, to save on book keeping. Rufus is a chronie for the Continuum, who is trying to make sure the future as he (and the rest of the Continuum) knows it. The phone booth was a jury-rigged time machine created by the Continuum because they didn't want to try and implant a time machine into them both and have them run amok through time and space.

Bowling and mini golf have ascended in respect by Rufus's time.
This is why he bothers to mention them at the start. They've ascended to the same level as the Olympics.

San Dimas Time doesn't apply to this film.
If it did, then there could be no fixed phone number for a specific day because the clock would shift forward 24 hours once every 24 hours. You would only be able to dial an era, like the lake-color system in the Xanth books.

This is critical because true San Dimas Time interferes with Tricked-Out Time -- you need precise timing to pull off Tricked-Out Time to the precision Bill & Ted do when the clock is always running, and they aren't that good at math. And it is Bill & Ted's recognition that San Dimas Time doesn't truly apply that allows them to write such a good, detailed report with so many special effects. There would be no time to set up the special lighting and props if Tricked-Out Time hadn't been used...

Note that Bill & Ted leave the school stage using the phone booth. It may be presumed that they arrived the same way. So, they just tuck themselves in a quiet corner of time for a few days or weeks to write and plan the report before they present it! Or after...

Everything happened exactly as history recorded it as happening.
Rufus was always supposed to be the one to go back and help the boys pass their history report, and DeNomolos was always supposed to attempt to prevent it from happening.
 * This guess is hardly wild. It's clear from the second film's ending that had DeNomolos not gone back in time and used his futuristic technology to put Bill and Ted in full view of the whole world, they couldn't have become the icons he was trying to prevent them from becoming.
 * Not to mention that those two medieval princesses turn out to be the rest of the band, meaning Wyld Stallyns absolutely must use time-travel to complete its lineup.

Ted's full legal name is Ted Theodore Logan.
Captain Logan doesn't seem like the most creative of men.
 * This seems possible, as his dad does seem like the sort who would whip out the "full name" treatment on someone at a moment's notice, so the fact that he calls his son "Ted" all the time might indicate that really is his given name.
 * Do we know that his father named him? Mr. Logan seemed to have a thing for dumb chicks.

The time travel caused all the historical figures they picked up to be killed
Most of the people they picked up didn't die quietly in bed. The phone booth time machine has a "doom aura." It even KO'd itself briefly.

Rufus visited Mr. Ryan at a point in time before the report was assigned.
Mr. Ryan was savvy to the whole time travel thing and gave Bill and Ted their assignment because Rufus took him to the 27th Century and showed him that the Wyld Stallions would effectively become Messiahs if they passed.

Bill and Ted created history and so could never have gotten less than an "A"
Bill and Ted didn't do much actual study, yet they knew an awful lot about the personages of historical significance they brought with them. How? They made it up! Then, when they returned the people to their own time, they simply did what B&T said in their report, thus making sure B&T's version of history was the correct one.
 * Er, they knew an awful lot about them because they're shown to be constantly referencing their history book. "I think he's under So-Crates."
 * But if they were learning everything from the book, why did they even need to go time-travelling? Unless you mean meeting the historical figures is what motivated them to read the book?

Bill and Ted didn't become famous because of their music skills.
Even if they were the greatest musicians ever,it wouldn't be enough to make the supposed perfect future.Rather,they became famous due to time travel.Using Rufus' time machine,Bill and Ted learned about all the secrets of history and became smart enough to make major technological advancements.The reason they didn't do it in the first movie was due to them not realising the potential of time travel.Future society simply thinks it was due to their music because said music was the beginning of their rise to fame,or simply because it seems cool.

Rufus never breaks the fourth wall.
He's a teacher. His opening narration is to his class, as is the "They do get better" bit. Either the movie itself is a reenactment or film he's made to show his class, or he has some sort of recording device active so he can show the class later.

Genghis Kahn's thrashing of the sporting goods store was brought on by a sugar rush.
He was lured into the phone booth by a twinkie and ate at the food court before the thrashing of the sporting goods store.

Rufus trusted Bill and Ted with time travel because they were too dumb to change history.
They didn't know enough history to, say, warn Abraham Lincoln that he was going to be assassinated, or that Napoleon would be defeated at Waterloo, etc.