I'm not 100% convinced these spells need fixing. But if I did feel that way...
Rope Trick, Downgrade 1: Make the spell (opening) visible, and if attacked and destroyed it ends the spell and everything falls out. (AC 10, HP 10 sounds about right ?)
Rope Trick, Downgrade 2: The opening emits a low hum. Enemies may become alerted to it with an appropriate check. Can be countered for the duration of the Rope Trick if Silence is cast during the casting of the Rope Trick.
Rope Trick Downgrade 3: The opening emits light as a hooded lantern, pointed downward. Enemies may become alerted to it with an appropriate check. Can be countered for the duration of the Rope Trick if Darkness is cast during the casting of the Rope Trick.
Tiny Hut, Downgrade 1: Remove the option to cast the spell as a ritual.
Tiny Hut, Downgrade 2: The spell slot for casting this spell is spent when the spell is over, not when it is initially cast (if interrupted, dispelled, etc, the spell slot is still used). Effectively, this removes one spell slot from a caster the day after it is used, rather than rewarding the player for keeping an unused spell slot until the end of the day.
Galder's Tower, Downgrade 1: Component - A 20kg rock, worth at least 100gp.
Galder's Tower, Downgrade 2: Casting Time - 2 hours.
Magnificent Mansion, Downgrade 1: The spell slot used for casting this spell cannot be regained until the spell's duration ends.
Magnificent Mansion, Downgrade 2: The servants in the mansion are sentient, and are the same for the lifetime of the caster. They will remember slights against them or boons paid to them. They must be paid just as regular workers (only for time when they exist), and will revolt just as real workers if not properly taken care of. Long terms effects of ignoring or mistreating the workers may result is strikes, rebellion, and damage to the mansion that can only be repaired by negotiating with the workers.