Does the two deities ever interact or ever mentioned together anywhere in Rigveda?
They don't interact (like Vishnu interacts with Indra in a subordinate role). But they are mentioned together occasionally:
One verse says:
“asya devasya mīḷhuṣo vayā viṣṇoreṣasya prabhṛthe havirbhiḥ | vide hi rudro rudriyaṃ mahitvaṃ yāsiṣṭaṃ vartiraśvināvirāvat |” (Rig Veda 7.40.5)
“With offerings I propitiate the branches of this swift-moving God, the bounteous Viṣṇu. Hence Rudra gained his Rudra-strength“.
There is a dual divinity Soma-Rudra
and Soma is called the father of Vishnu in 9 96 5
"Father of holy hymns, Soma flows onward the Father of the earth, Father of heaven: Father of Agni, Surya's generator, the Father who begat Indra and Visnu."