No, grapple and shoving attacks can be performed on creatures only.
You quoted the relevant rules: both attacks require that the target be a creature.
In particular, about your listed entities:
- Bigby's hand is an object, not a creature: it can grapple because its description says so, under the Specific beats general principle.
- Guardian of Faith is neither a creature, nor an object. It does not provide any stats block, nor point to a Monster stats block. Moreover, the spell description does not provide any partial stats (AC, HP, attacks) that might suggest a DM ruling in that sense.
- Spiritual Weapon is...a weapon. You can check the difference with a Flying Sword, which is technically a creature and hence can be grappled and/or shoved.
- Unseen Servant is not a creature either.
A DM has always the final word.
The above considerations are based on the direct application of the rules. A DM has the final decision, they may allow these kinds of attack even for objects and for other entities (such as an Unseen servant).