Kia-en

The DLC map has rare items and you can keep playing and obtaining them over and over. Kouli on Gamefaqs said he already had 5 Thunder Swords by Chapter 11 and he also got a Hammerne from the DLC map.

You can also buy them normally. Someone mentioned on Gamefaqs that a merchant sold him both Change and Promotion Seals for only 2500 Gold. He was probably playing on Normal though (the items cost more on harder difficulties)

From what I read on gamefaqs, leveling to 20 is not effective. The game keeps track of how many levels you've leveled and uses that to calculate EXP. For example, if you take Sumia, level her to 20 Pegasus Knight and the change her to Falcon Knight, she counts as level 21. Then level her to 20 and change her to Dark Pegasus, she counts as level 41 (and probably gains very little EXP). On the other hand, you could level Sumia to 10 as Pegasus Knight (to get both skills), then change to Falcon Knight (counts as level 11), level to 15 to get both skills and change to Dark Pegasus, which would count as level 26. The second method gives you all the skills but you'll be gaining more EXP. It would use more change seals before getting max stats (since you change class once you get to 15 promoted instead of 20) but you'll be able to get the skills from other classes faster (because EXP won't be reduced as much). It seems you can buy them after Chapter 12 or so.

Maybe, but male MU can't change into Pegasus Knight and learn Lighting Speed... but Olivia can, so maybe she can pass it on to Mark. I doubt it though.

Sounds possible except for... how ar eyou going to learn Lighting Speed on a male MU?

No. That page even says: The result of the fortune-telling is completely random and has nothing to do with the main story.

Someone said they were only 2500 Gold each (promotion items too). Probably on normal though. Besides we are talking about "broken" or "optimal" builds, we should assume you have enough. It's true we don't have stats yet, but it's still fun to make them based on weapon choices

We don't know the stats yet. I decided on Valkyrie for now since it can use magic and staves... plus a horse.With Lighting speed it can attack and then heal, unlike other healers that might only be able to heal once per turn.

Levin? http://serenesforest.net/fe13/post/levin.jpg

That's more like optimum rather than broken. The best I can think for Mariabel (Valkyrie): Lighting Speed Renewal Magic Expert Life Absorb Magic +2 / Dual Support / Secluded Lady Actually, that doesn't look too good.

Because that's boring... Besides, on Lunatic they might still hit you a lot.

Support MU: Secluded Lady Crimsom Curse Curse Rainbow Cry Movement Cry? Lighting Speed? Movement +1? Pick Lock? Tank MU: Alone or keep him in Dual mode. Renewal Life Absorb Sol Grat Shield or Dual Guard+ Holy Shield or Dual Support+