Ok, should I go with the installation order in the FCOM cheat sheet or should I install MMM last before FCOM omod?
That's not very important. MMM now has all its resources in a bsa file, so it no longer has any resource files with the same filepath as OOO resources. Thus the two mods will no longer overwrite any content of the other. My MMM installer automatically detects the other mods if they are installed, but if not, it will ask you if you plan to install the other, and if answering yes, it will install the correct files anyway.
On the side note, if you look at the FCOM cheat sheet it says that for OOO you need to select the "Full" version and ignore the extra options. What extra options? somebody already told me that they are refering probably to the options related to the "lite" version BUT in the "full" version I get options like if I want x amount of spawn points, x amount of combat behaviour, Harvest[flora], etc. Some of this options can be set to "no" but others like X amount of combat behaviour are something that you have to choose from the list provided. I'm a bit confuse here(i'm using the recent OOO omod version)
It must mean the Lite version, because the other options are generally fully compatible with FCOM.
Note that the included version of Harvest Flora is obsolete, so you should say no to that and rather download the standalone. Same is true for Living Economy, although I will suggest my own Enhanced Economy instead, since it not only has many more features, but is also more compatible with FCOM than what LE is.