I married Jordis this playthrough and I know I could make her join the Blades before I married her. Can I still do it? And if so, what happens? Will she lose all the armour and gear I crafted her? Will she move to Sky Haven Temple? If she moves to Sky Haven, can I make her come home? Will she hate me if I don't kill Paarthurnax?

The Spouse lives where you tell them to. Not sure if the Temple would be a choice they would offer you as a place to live (as opposed to their own house if you don't want to live in their house)

As for the Blades and Paarth, not sure, but she will not have any dialog (probably won't anyway) to go against your choice. I also have to ask, if you left Paarth alive, then why are you messing with the Blades? You are at cross purposes with them now. They won't complete quests for you.

Not sure why joining a faction would make them change armor. Do NPCs even get the reward armor? If the reward armor is less DR than what she currently has (with regards to skills), she won't wear it anyway.

I just got asked by them to kill Paarthunax, and have never done it before so am probably going to do it this time just for something different. And, I didn't know if it was a scripted thing where all members of the Blades equip their armour after joining the faction. Both Mjoll and Erik the Slayer have the Blades gear equiped now. But, they were both wearing stuff that was less effective than what the Blades gave them when I sent them to Delphine.

edit - in one way I thought it would be kind of cool to be a husband wife dragon slaying team. But then I thought, who wants to work with their wife? I know I don't irl.

I just got her to join the Blades and she now has all the Blades gear equipped. All the armour she was wearing when I asked her to join is now gone, but the weapon and jewelry I made her is still in her inventory. So apparently when anyone joins the Blades they equip theri armour regardless of what they have on at the time.

Anyone joining the blades will equip blades armor.

However if you just sent your wife there, its doubtful she will ever return home. Once a blade, always a blade.

What was the specs of the armor that she had on? Do you remember?

Maybe it would be best to take the stuff away before you send them to the blades, if the armor had any value.

That might be the one exception in the game to how the NPCs choose to wear armor. Wonder though if you have them follow you, will they change back into the stronger armor if they have it?

It's a set of dual enchanted legendary ancient nordic armour. The armour itself has an AR of 124, and the boots and gauntlets have an AR of 58 each.

edit - the set of Blades armour I got when I went to Sky Haven Temple for the first time has an AR of 104 on the armour and 32 on the boots and gauntlets.

It is an exception, the NPC's default armor is changed to blades armor.

I saved right before I did it, so this was more of an experiment than anything else. I'm going to let her stay in Falkreath and get someone else to join the Blades.

There's a window of time (after you take D&E to Sky Haven Temple, but before you learn Dragonrend) in which you can recruit Blades members and do Blades stuff. After you've learned Dragonrend, though, your next interaction with D&E gives you MQPaarthurnax.

@OP:

-You risk losing any non-default items that Jordis might be carrying when she's inducted. You can safely equip her afterward.

-Her "home" becomes Sky Haven. However, you can still have her live in your home. If you live in hers, however, it will be Sky Haven.

-She won't suddenly hate you (unlike D&E) if you acquire MQPaarthurnax. Note that if y'all are living in Sky Haven, any stored conjugal property will probably become Blades property for stealing purposes. You will still get normal wife (and follower) interactions with her.