So, are the bonus endings supposed to be semi-canon?

[Satoh]

Age has nothing to do with monarchy. You can be queen at 12 so long as you're married to an eligible male...

And besides that, the presence of a chancellor points to the fact that they may not actually be running the country at all. They're figureheads on the throne while someone else acts in their interest.

Just being a king or queen doesn't mean you're worth anything really.

[Rocky]

Marle, who is about 16, is mistaken for Leene, which means that Leene is around the same age.

A serious problem, you say?  Game script, to the rescue!

 [Young Woman]
   The Queen married into the family 10
   years ago.
   She still looks so youthful!

   In fact, she looks even younger now
   than on her wedding day...

That completely answers your quandary.  She says that she (Marle, perceived as Leene) looks even younger now than on her wedding day.  So let's say Marle is 16.  Then Leene might have been 18 when she got married.  (You can see her in Glenn's flashback as he and Cyrus leave the castle - she's already married, and the queen.)  Which would mean she's 28 at present.  Twelve year difference too hard to believe, mistaking one for the other?  Well, I'm 28, but when I look at a picture of myself at age 18 or even 16, it's not all that different.  Still young enough that wrinkles haven't set in, and I even pretty much style my hair the same way.  (I've put on quite a bit of weight, but many people don't.)  The point is, facial features don't change drastically by that age.

But keep in mind that the woman even admitted that the "queen" looked even younger than she did 10 years ago.  So she directly tells you that there is a perceived age difference of over 10 years.  People still assumed she was the same person because looking younger is more believable than assuming she's a completely different person, a descendant from the future.  (Also worth noting is the fact that a descendant would never be seriously mistaken for their ancestor, as if they were twins.  This IS a video game, after all.  And it's Chrono Trigger, an admittedly simplistic game [which I love, heh].  If they could somehow look identical...well, the age difference is really no big deal by comparison.)

To clarify my earlier point, I don't think there is open love between Glenn and Leene at any point during or before the events of Chrono Trigger.  It's something that simmers under the surface due to their intimate friendship - a "pure" love with the potential to grow into something else.  I think that's what Glenn sees and couldn't let continue.  (This isn't the same as Crono and Lucca's relationship, which is more sibling-like.)

Fair enough - we just perceive things differently.  I will say that even if Crono and Lucca are more like siblings, that doesn't rule out the potential romantic feelings.  (See:  Boone and Shannon, characters that are step-brother and step-sister, on "Lost".)  Whether sibling-like or as a servant to the queen, feelings are equally possible to develop.  I personally don't see the evidence in the game to support romantic feelings in either case.  But again, we just see things differently.

[Rocky]

Just an added thought.  Admittedly, a close friendship and "something more" are two things that are sometimes hard to tell apart.  So it makes sense that there can be differences of opinion.

But I wanted to add some further dialogue from the game, regarding the relationship between Leene and her husband:

 [Knight]
   The King was injured, and is
   recuperating in bed.

 [Knight]
   Queen Leene has been at his side all
   night.

(And you actually see Leene at the King's bedside during that section of the game.)

And I just thought I'd add the following for the heck of it.  It's part of Leene's letter to Marle, near the end of the game:

   But nothing can break your bond of
   blood. Neither words of anger, nor
   great distances.

   Someday, when you have children,
   you will understand.

   This special bond is part of a family
   tree which links us together.

I only included that because it exudes her strong feelings, her joy, with regard to her family.  Basically, she doesn't appear to just be married, she actually seems happily married, very content.  And as shown by the earlier quote, she remained beside her husband's bed all night, while he was injured - certainly not an obligation, or a pretense.

Doesn't prove anything, but it does show that she didn't regard her marriage as an obligation - her heart seemed truly vested in it...IMO 

[Nangbaby]

I think some of the endings are joke endings, but I don't think the Reptite ending or Leene/Frog ending are completely out of the realm of possibility.  I think the idea is, "What if Crono had not continued on his quest and was not forced to continue?"

Concerning the Reptites ending, kidnapped the humans and held them prisoner in the Tyrano Lair.  This would have prevented them from escaping to survive to propagate.  I don't believe every single Reptite died the moment Lavos fell, but that the fall of Lavos did decimate them and the remnants slowly they died out afterward.  With the humans more able to adapt, they would easily eliminate any remaining Reptites.

However, if there are no humans left, a few Reptites could survive and over time restore their civilization, one that would develop similarly to that of humanity.

Regarding Leene/Frog, there may have been change in the past hinted in the game itself -- the King's death.  If the party never comes back, to the past, the battle on the bridge may have been lost, which could break the King's heart and kill him in his precarious condition.  That might be just the event to get Frog off his duff and try to salvage the remains of the kingdom.  Since Magus would be killed by Lavos anyway, the Mystics would lose the war through the disaster known as Ozzie's leadership.  Without a king or an heir, though, Guardia's going to have a succession war.  Solution:  quickie secret "marriage" (this is a game aimed at a wide audience, but you know what I mean) to Leene to have her quickly conceive an heir, then they just say that the child was conceived before death.

(Or alternately, Leene and Frog had an affair, but with the King's death, hey, no more need to hide it.  Unlikely, though.)

[utunnels]

It just means similar things can happen in a reptite world IMO. The reptite dude doesn't have to be the same Crono. Think about Robo's ending in which he bumps into Atropos.

So even if it is a joke, it is still a cool idea. It reminds me of the multiple dimension idea of CC.

[Crono666]

Tata venturing through Magus's castle, and running into Crono, Marle, and Lucca laughing maniacally, appearing to be bad for some reason?

Yeah I still don't understand that ending.

[Rocky]

Yeah, I thought that was an important one to cite, based on my subject title.  If these endings are kept in the category of "funny what-ifs", then yeah, there's no problem.  But if they're supposed to be even semi-canon, that's where I have trouble getting on board.  Crono & co.'s appearance before Tata in Magus's castle is one reason.  And though there are apparently many who think the Frog & Leene thing has a potential basis in canon, I don't.  In my personal perception of the game's events, those two endings (at least) don't fit in with the main game's reality, even a little.

As I said, just in my perception.  I'm only one person. 

[Mr Bekkler]

I took that ending to be an intentional wtf, a joke like the "slideshow" ending.