No the Android version of Minecraft cannot currently be obtained for free with a Windows 10 version of the game.

The only promotion they have done like this is if you had Minecraft Java Edition for PC or Mac you would get a free licence for Windows 10 Edition

No, the Android version of Minecraft cannot currently be obtained for free with a Windows 10 version of the game.

There used to be a promotion for owners of Minecraft: Java Edition though:

Players who have purchased Minecraft: Java Edition before October 19th, 2018 can get Minecraft for Windows 10 for free by visiting their Mojang account.