I would like to grow certain plants in a self contained habitat (like cattails, fireweed, thistle, and other edible plants that are semi easy to maintain) but I read that siblings can’t pollinate each other. Which means that I can’t just grow a garden out of two of the same plant. How many plant families would it take to make sure all plants has a pollination partner?
Either you are using terms like "family" incorrectly or there is a basic misunderstanding here.
Plants from one species are (normally) only pollinated by other plants of the same species. Edible plants, and cultivated garden flowers, often have many different varieties within the same species - for example all the named varieties of tomatoes or roses will pollinate each other.
You may be confused by the fact that some individual plants (e.g. apple trees) can not pollinate themselves, and in some species each plant only has male or female flowers. Some other species have different male and female flowers on the same plant.
In some self-pollinating plants (for example peas) the flowers are actually pollinated before the flower buds open.
The idea of a "species" can be confusing though. For example many the commonly grown types of brassica (cabbage, cauliflower, brussels sprout, kale, kohl-rabi, etc) are actually the same biological species (Brassica oleracea) and can cross-polliate each other, even though they look quite different. But when they are grown as vegetables, you don't want them to flower and set seed at all, so that is irrelevant in practice.
To summarize all that, unless you want to grow only one single plant of a particular species, you are unlikely to have anything to worry about. Any plants that are usually classed as "weeds" will be prolific at reproducing themselves, without your help.