How do Thralls work

Solution 1:

Thralls are not equivalent to followers

According to the Unofficial Elder Scrolls Pages:

• Dead Thralls will equip any weapons and shields that you place on their corpse prior to reanimation (requires a loading screen or engaging an enemy to initiate equipping). Just like other followers, they will prefer weapons according to the quality of the material rather than the smithing level of improvement. They will also use staves, including those which summon or reanimate, and will often prefer them over melee weapons.
• Dead Thralls will only equip the exact armor that they spawned in, so a corpse wearing a full set of elven or glass armor may be more durable in combat than a bandit in fur armor. You may take the armor from the corpse in order to improve it, enchant it, and even rename it and then replace it onto the thrall, but it must be the very armor the thrall spawned in for them to re-equip it, not just a similar item with the same name. [...]

This implies that you cannot talk to them and trade equipment, because otherwise it would be unnecessary to interact with the corpse.

Since you can't resurrect your housecarl, you may want to find a new one. There are a total of eight housecarls, one for each hold except Winterhold. You obtain each housecarl by becoming thane of his or her hold.

You can only become Thane of Whiterun by following the main quest. The general process for the other eight holds is described on UESP:

1. You befriend the jarl through a quest or favors.
2. The jarl asks you to demonstrate your value to the hold by assisting the people (five people in holds with major cities, three people in the other holds; in the Rift the conversation with the jarl is skipped, but you still have to help the people).
3. The jarl asks you to purchase a house in the city (if the hold has a major city).
4. The jarl grants the title of Thane and all that comes with it.

For seven of the holds (all except The Rift and Haafingar), "a quest or favors" includes installing a new jarl either via the Civil War questline or via Season Unending. Maven Black-Briar (Riften) will take over Laila Law-Giver's thaneship quest instead of giving you a freebie, and Elisif the Fair (Solitude) remains Jarl of Solitude regardless of Ulfric's victory. However, it is not possible to remove Jarl Balgruuf the Greater of Whiterun without first becoming Thane, because he blocks the Civil War quest until the main quest has been sufficiently advanced.

Thaneship lapses automatically when the hold changes hands during the Civil War or as a result of Season Unending. For holds other than Whiterun, this makes little practical difference because the prerequisites carry over, so you can just ask the new jarl to reappoint you. For Whiterun, you will be asked to go through the usual "help people and buy a house" spiel (which you skipped the first time around). Regardless of your thaneship status, your housecarl remains loyal to you once appointed.