Regarding missable content, only the bare minimum. These are the more or less obvious choices, like losing the v-card or scenes related to picking your #1 lady (and related). The total majority of content will be doable in a single playthrough. I am not a fan of the content locking.How much stuff will be missable between routes? I expect that certain choices on any girl route will give different scenes/endings, but will we be able to progress all routes at the same time? The same as in FutadomWorld? In that game after you are done with a girl you can start from 0 with any other without fearing you missed something, only within the route you just did. Will you make the routes in this game separate or do they interact with each other?
The routes will be separate, though if two (and more) characters know each other, they will interact during their storylines accordingly. That means open doors to (optional) threesomes and related fun.