But do the containers?
If they don't, then it CAN be ours.
Both the UESP and wikia claim that the containers are safe. The wikia might be a little too optimistic in it's description, though:
After the quest Scoundrel's Folly, you receive a Goldenglow Estate Deed, and then it's yours. Every container is marked "safe". All smithing essentials are outside. There is no Alchemy Lab or Arcane Enchanter nearby. The mercenaries will still be hostile towards the Dragonborn and continue to respawn if killed.
While you may posses the deed, you basically just have squatters rights like with any other abandoned home found in the world. Spouses cannot be told to live there, for example. And as stated, the hostile mercs respawn. They are pretty tough customers for mid-level players so they pose something of a nuisance.