Is there a way that a friend with his Xbox One but without Xbox Live Gold can play Minecraft with me (PC) together? So far it does not work, because there's no gold on the one.
You can't play it together with the gold cocker either there are 2 different editions PE can't keep up with the PC version either
No, there are different things
Xbox One can play with Xbox One and Pc can play with PC
Basically, online gaming on console also requires X-Box Live Gold.
On the other hand, not all games support cross platform gaming. I just think of Rocket League, Sea of Thieves, War Thunder or State of Decay. For more titles probably only an online research helps.
PC and mobile phone can be played together.
Minecraft now supports Cross Play (Minecraft Windows 10 Edition)
The Minecraft version I have supports Cross Play on PC / XBOX / iOS and Android
In the meantime it works, with the Minecraft Windows 10 Edition computers can play with XBOX players. But I do not know if you need XBOX Gold for that.