There is another possibility. If you talk to Flemith she will offer you a deal to give you Morrigans grimoire. This suggests that nothing in the Grimoire can harm Flemith and may be actually part of her plan. Perhaps she planted ideas in her Grimoire for the contingency that Morrigan would get it, either by Flemith being slain or you making a deal with her. Perhaps it has been her plan all along. Flemith has prepared Morrigan as her vessel and everything about Flemiths teachings is about survival. love is a weakness. And it is easier for her to enter the vessel the more powerfull the vessel becomes in magic, like the spells in Flemiths grimoire. Morrigan is unsure herself that this god child she will raise is the answer but the important thing is she believes it is her best chance for survival and got the ritual information from Flemith's grimoire. Why would Flemith give that freely to anyone let alone the vessel she needs for survival? Perhaps it is because she knows the vessel will use it out of survival instinct that she has so thoroughly prepared.
On my first play through I loved Morrigan and refused Morrigans offer, tried to convince Alister but he would not have it (thereafter new characters I make sure to max persuasion skill) and I performed the ultimate sacrifice and got a message at the end after my funeral that she was seen with child. I thought maybe it was a broken quest so I backed up to the save point before Morrigan gives you her grand plan and repeated it through saying no but there it was again. Not Alisters and I had said no. Course we had been together before that point...and maybe that save is borked I don't know, but I don't think so. So then I backed up and agreed to the ritual and got the part in there at the end about the "rumor that she had been with me". And that all I could sense through the ring was remorse and sadness. I relate this because I have seen other people say they get the message that Morrigan gets eaten. I wonder if thats because they didn't love her and had never been with her I don't know. All I know is I can't seem to get that whether I say yes or no from that save game.
So ok time for second play through, although after so much backing up on the first play through I felt like it was my third complete play through... I created a new character and played all the way through to that save point this time making sure to max persuasion skill. This character loved Leliana +100 and had Morrigan at +100 Friend! And this time convinced Alister to marry Anora and say yes to Morrigans ritual. We both survived, Leliana and I went traveling, Alister was King with Anora the Queen and got the message again that Morrigan was seen with child. So you think Aha! Maybe Alister did do Morrigan the first time even though he said no. But not so, I never got the cutscene with Morrigan and Alister on the first toon but I did on the second toon. Course that could also be a busted quest symptom...
The play through I have not done yet is to not give Morrigan one or both grimoires. On my to do list though. But I do think it is possible for a sequel or DLC with Morrigan. After all you can choose the ultimate sacrifice so what does that mean no more DLC for you? I don' think so LOL. Bioware will ensure there is a way to sell you more DLC. The only question is what will sell.
Assuming it's not a busted quest, it seems odd to me that Morrigan can be seen with child three ways, you saying yes, Alister sating yes, you and Alister both saying no, to have nothing come of it. But Bioware will put together what they think will sell and if people are interested in the Morrigan theories and plot lines then I think they will. I for one find it very intriguing and would be very interested in such DLC. For toons that did not give Morrigan one or both Grimoires then perhaps you will have a different meeting with Morrigan a.k.a Flemith but still meet. Morrigan is after all trained by Flemeith, the ultimate survivor.
Another idea I caught myself thinking was that upon slaughtering Flemth, perhaps she had possessed Morrigan at that moment even though Morrigan was back at camp. Morrigans demeanor does change (and I don't mean the slider bar). This could be because she realizes she now has a chance or could be because she is now Flemith. Even Morrigan says Flemith could come back even if she is dead. Morrigan thinks that by killing Flemith it will just give her time, time to strategize the survial plan, which may have been Flemiths plan all along. Perhaps the child will not have the Arch Demon soul to battle Flemith, perhaps it will be Flemiths soul or something totally different, a benevolent spirit or old god. Perhaps the Arch Demon/Tevinter/old god soul is a catalyst. And perhaps when the character sensed remorse and sadness through the ring, it was Flemiths for perhaps she realized that the character was not like her husband that sold her so very long ago. Or perhaps thats what she is counting on.
Remember that vessel that views love and loyalty as a weakness? I would prefer to think that whether I love Morrigan as a friend or a lover, the goal is to unshape the vessel Flemith created, to reshape Morrigans core foundation to the point where she is alien to Flemith to make it more difficult if not impossible for Flemith to find her let alone possess her. An ironic survival tactic in itself no?
But perhaps Flemith had a counterpoint ready for that contingency too, perhaps she was counting on love getting the better part of her vessel as it did her so long ago.
I would prefer to think that as either a friend or lover we would wade through rivers of demon and abomination entrails left in our wake as we slaughtered through the depths of hell to find and put and end to Flemith once and for all, with or without Morrigan. Now that I think, would be something Flemith would not expect, a friend or a lover that would stop at nothing to save her, for that is something Flemith never had even for as beautiful as she was, hence her preoccupation on survival and *her* weakness.
It could be that the blight, the arch demons, Morrigan, the child, the grimoire, the ritual, all counterpieces that fit into Flemtihs masterpiece or perhaps put into motion by herself long ago to garauntee her survival. A tune and dance known well and performed many times...
Tis fun to speculate. There are always ways...the imagination is endless. Bioware can spin this however they want. I doubt we'll ever hit on it if they do decide on a Morrigan continuation one way or the other, as there is always a "loop in your hole" as Morrigan would say. We will have to wait and see. But if they do, I for one would say;
"A fine gift, you have my thanks."