Will rainwater automatically contain the novel life forms that promote human well being and longevity?

Rainwater, for the most part, will be devoid of these life forms. As you surmised, the condensation of water vapor is bringing the molecular form to create an aggregate that coalesces into droplets. Being in an isolated state, as a gaseous form, separates it from everything else, including any kind of life form using it as a vehicle, so, in a sense, the process of water distribution through rainfall is a purification applied naturally to cleanse the water of everything of a particulate nature and any indwelling life forms. It is contact with the Earth, and other water in contact with Earth, that disseminates the novel life forms and allows them to thrive. So rainwater added to reservoirs will simply intermix and then acquire the desired natural properties of benefit, but capturing it as rainfall will not be equivalent in conferring this benefit.