On three different characters, I get a letter from the Jarl of Falkreath once I hit level 9. Do you not get an invitation from the other Jarls?

I don't think you do. Just go directly to Morthal and talk to the Jarl. Do a certain quest for him and then you should be able to buy the house from his steward. I haven't bought The Pale house but I believe it's similar. You need to be a certain level though to do the quest (22, I think).

There's no level requirement for "Waking Nightmare" in Dawnstar. You can do both this and "Laid to Rest" attaining both houses whenever you wish.

Didn't know this. I just went back to look at UESP and this is what it says:

"Located in http://www.uesp.net/wiki/Skyrim:The_Pale, this plot of land may be purchased from the http://www.uesp.net/wiki/Skyrim:Jarl of http://www.uesp.net/wiki/Skyrim:Dawnstar in http://www.uesp.net/wiki/Skyrim:The_White_Hall. You will have to complete the quest http://www.uesp.net/wiki/Skyrim:Waking_Nightmare, and then the favor quest http://www.uesp.net/wiki/Skyrim:Kill_the_Giant_%28Jarl%29 before being allowed to purchase the property. (Note: This favor has a prerequisite of being level 22.) If you are http://www.uesp.net/wiki/Skyrim:Thane of the hold, you will be appointed a http://www.uesp.net/wiki/Skyrim:Housecarl named http://www.uesp.net/wiki/Skyrim:Gregor."

That's odd. I could have sworn I received "Kill the Giant" at a much lower level. Perhaps I was mistaken. Gonna test.


EDIT: My mistake. I confused one of my character's with another, so it seems the house in the Pale can't be attained until level 22.

My second character left all the Dawnstar quests, since she was not sure what to do about Erandur, wanted to see if she could marry him, or be the first character to kill him. Not marriable, killed him, was not impressed with the staff and ended up leaving him alive anyway. Recently got the land, built Heljarchen Hall and looked around thinking something was missing. No housecarl! Rushed back and did a couple of stints at mining, and delivered a message from one of the mills to become Thane in the quickest possible way. But I remember my first character had to wait a while before he could be Thane in Dawnstar, he started a lot earlier. Had everything possible done before the giant quest came up.

Each house deed can only be obtained (with the exception of Falkreath) by completing a certain quest to have the option to purchase a house deed. I forgot which quests but you can search the Elder Scrolls Wiki for help.

I only got a letter from Falkreath and Whiterun. No problem with getting land from Morthal or Dawnstar. Just no invites.

I'm assuming the kids room change is available in other houses (until I see otherwise).

You only get the invite from Falkreath. Other hoses are obtained through certain quests. And yes all houses in Skyrim have the option to have a kids bedroom put in.

You can have a children's room in all the main game houses, but save before you buy it in case it cost you more than just money, the extra room will replace some things in your house. Breezehome will not only take the alchemy room, but apparently also the barrel under the stairs. Proudspire is a new room that will only cost you the two bookshelves outside your bedroom. Hjerim will cost you the cupboard near the secret door. Not sure about the others.

Arcane enchanter is replaced in the house in riften (breezehome)