I would never buy a house with friends. Your own life can be unpredictable enough. Hedging your bets that these friends will remain in the same stable position in their lives is too much uncertainty. What if they get divorced? It might seem improbable, but that happens to people, even those who have been married for decades. What happens if they run into unexpected financial difficulties and can no longer afford their portion of the mortgage? What if they need to sell their portion of the house, and you are not in the position to buy them out right when that happens? There are far too many what ifs. Do not do this.
I would definitely approach the landlord as swiftly as possible, just to float the idea that you are interested. You never know, they may like the idea of selling off the property quickly. I will say, as a warning, my parents were these kinds of landlords. Bought rental properties when they were starting out, then never increased the rents for 40 years. As it turns out, they were not suited to be landlords, and had to interest in it, even with a management company to handle any issues. Just ignoring it all together turned out to be the easiest option for them. But that also means the hassle of selling held no appeal to them either - too much paperwork. Which might be the situation you are in.
#BidenHarris2020 “It’s easier to be a parent this morning. It’s easier to be a dad. It’s easier to tell your kids character matters. It matters. Telling the truth matters. Being a good person matters.”