In most eras, this was handled by having a range of diverse crops. If wheat failed, rye might be alright. If the turnips didn't come in, there was probably cabbage. If something happened to the cows, there were sheep as well. But these were measures of limited effectiveness, and they were dependent on local conditions too - if your farm is in chalky uplands, then you're just not going to be able to keep many cattle compared to the number of sheep, for instance.

I'll run through some of the details of your question, but I'd like to talk a little bit first about the concepts here. Bear in mind that while economic history touches on a lot of what I do, I'm not an expert! Futures markets essentially depend on there being a cash economy (or something else with a standard medium of exchange), but for much of history, the cash economy was a very small fraction of the overall. And the motive of profit wasn't necessarily a real one - in medieval Ireland, for example, power was demonstrated by giving things away, not by possession of money or even goods, and someone acting for profit would probably have been viewed as being a bit wrong in the head. Guesthouses, run by the high-status briugu, provided hospitality for free, and received grain, money, and other supplies from kings and other notables for that purpose. In England, very few of the monarchs before Henry VII show much interest at all in the balance of money in the present coffers, let alone the future, and much of the nobility would have fallen in line with that. Good land management or the development of alliances was regarded as being of much higher importance than mere profit. And below these higher-status ranks, the concern is much more with survival, not profit.

Insurance wasn't a concept that pre-Modern people would have been familiar with, either, until about the 14th century in Italy (although there are some related concepts as early as the Code of Hammurabi). What was more common was a sort of mutual-aid group; usually a guild. Members contributed to the coffers of the guild, and that money was then used to rescue members from disasters of various kinds, maintain their widows and children if they died at an early age, and so forth. These are better thought of as being vaguely like pension funds rather than insurance - but you couldn't just buy into them; you had to be in the right social group, profession, etc. Additionally, there were long-standing arrangements between noble families, called patrons and clients, in which one party could be relied upon to bail the other out in times of need.

Savings rates were also different. There is just about the concept of a deposit account, to which the banker would add a 'gift' every year - this being part of the dodging around the sin of usury (charging and sometimes paying of interest), which was treated with varying degrees of seriousness up to the modern era. But only the very richest of people, who had cash to spare, would use them, and they were usually not people with occupations, as such.

So. Farmers usually tried to handle uncertainty via diversity. Most of the ways in which goods are currently taken to markets were either unknown or illegal (the crimes of regrating^1, forestalling^2, and huckstery^3, all of which seem utterly bizarre to the modern mind), so they were dealing directly with the people buying from them, in whatever way. But in many cases, if a main crop - wheat or other grains - failed, then they were in for a tough year, and there was no way around that.

Butchers as a trade seem to be a relatively new thing; meat remained on the hoof until just before it was slaughtered, and that was generally done by the household that was going to eat it, until cities got big enough for specific meat retailers to be useful. Importers, exporters, and shippers were such a minority as to barely exist, but where they did, they would have had guilds in some form, and would have had fairly diverse 'portfolios'. Miners, as almost the most basic of labourers, were rarely affected by commodity prices - they dug stuff out and sold it for whatever it got, in some cases, or they dug stuff out and got paid a day's wage for it in others. Blacksmiths would often have had other trades to fall back on (usually some farming of their own), and would have re-used metal rather more than we'd expect now, or would have been employed by larger households, and had the resources of that to back them in times of trouble - so were less affected by a broader concept of the price of iron or coal than we might think. The resource for them was the skill of manufacture, rather than the material as such.

^1 Buying goods in small lots and selling them together
^2 Meeting goods coming to market, buying them up and reselling at a higher price
^3 Buying goods and reselling from a tray or wagon

Sources:

Tim Parks, *Medici Money: Banking, Metaphysics, and Art in Fifteenth-century Florence

Raymond De Roover, The Medici Bank: its organization, management, and decline

Steve Hindle, 'Rural Society' in Beat Kumin, The European World 1500-1800

Grenville G. Astill and John Langdon, Medieval Farming and Technology: The Impact of Agricultural Change in Northwest Europe

Bruce M. S. Campbell and Mark Overton, 'A New Perspective on Medieval and Early Modern Agriculture: Six Centuries of Norfolk Farming c.1250-c.1850' in Past & Present, (1993) No. 141, pp 38-105.

Christopher Dyer, Making a Living in the Middle Ages: The People of Britain 850-1520