welll…
what you are asking, it is a bit of a time consuming process. but you can do for the most part all of your points
and what effective way to learn, than to begin step by step 
just like my teachers have done.
“if you teach a man how to fish” type of situation.
for starter, very nifty tools and some basic understanding:
how to remove " stuff ".
in enlisted, there are 2 ways to remove buildings.
scenery_remover
1st method is through scenery_remover
what you’ll need to do, is first to open the entity menu ( the emoji icon ) which you can open with it’s default hotkey T
next, select the first bold white text and select " rendinst " ( you’ll have to scroll a bit )
click on the scenery_remover and place it on the general area where you want to remove things as a starter point:
you’ll be left with a box.
the next step, is to enlarge the box to contain all the things that you want to remove.
in this case, we’ll have to scale it.
which you can do by pressing R
and as you can see, the shape changed.
now you can scale the various axes ( or all of them 3 through the central part or use any of the yellow edges and drag them up )
in my case, and most likely in the future, you’ll need to rotate them. as in my example, to follow the shape of the house. hence, i’ll need to rotate it.
and you can do that by pressing E
which the shapes will change and you can now rotate them through various axes.
Make sure to always move around with the camera ( by pressing Space ) to look around and see if what you are trying to remove is fully inside the box.
in my case, it is.
hence, now open the property panel ( in case it’s not open, the window on the right, press P )
and check the " scan " box
you’ll notice a blue bar appearing telling you that some items were scanned:
and once you are pleased with the selection, just hit the: " scenery_remover_apply " at the top. and voilĂ :
all of the items are gone.
if you do not like the selection and want to revert it. you’ll have to delete the scenery remover and everything will be restored.
currently this item is very user friendly. although, sometimes it may detect things outside the box. ( this only happens with larger buildings due to hitboxes. which if you do, you’ll also want to use the second method to detect and scan the various items and then incldue them in the scenery_remover_exclude. which you can press a plus and just paste the names. )
through rendinst toolbox
this is one also somewhat simpler, but the less optimal one.
mostly because if you plan on removing lots of assets, this can lead to your files being generally heavy and processing intensive. which may result in your map not loading.
anyway first thing first, you’ll want to select at the top, " toolbox "
and a sub menu will open.
after that, click the " rendinsts "
the cursor will switch to be a box. you’ll know you are in rendinst mode.
after that, you can click an item ( ore more by holding CTRL )
and each item that has been selected, is highlighted with circles around said items.
from there you can just hit canc, and they will disappear
if you don’t like what you have deleted, you can press CTRL+Z and restore them.
not ideal if you have deleted many things though. and you just want to reverse one of the first.
otherwise you’ll have to look through the blk, and remove it manually from the code.
alternatively, if you want to select more things more fast, you can hit the " within " button a couple of times, and it will select more objects in the vicinity:
and if you want to exclude something from the selection, you can hold CTRL+LMB1 ( left mouse button 1 ) and click on a selected item ( in my case, i’ll deselect the base house. just to select the details and rubbles ) and then Hit Canc:
How to Clone Stuff
cloning allows you to reuse assets or clone already existing assets to make duplicates.
it’s fairly easy and uses somewhat the same method as the surgical way of removing things as previously shown.
i assume you followed that part, but if not, worry not.
clone method
all you will have to do, is find the object/s that you want to find and clone. in this example,
i want to clone this PzIV F2: ( but it can pretty much work for houses, objects etc )
from here, select the " toolbox " on the top right corner, and click " rendinsts "
which it will open a sub menu and you will notice that your pointer has become a square:
with that square, select the general area if your item:
and click " within ".
this will select most objects within the item that you have selected. i reccomend pressing it multiple times as it may not always select everything close to it.
but as you can see, it selected most of the objects
after that, you’ll want to click/hit " Instance ".
upon clicking it, it doesn’t seem much has happened, but the selected box that from white became red, means the item has been cloned, and you can move it around and place it where you need it:
( Press W as the " moving things " hotkeys, and you will notice a bunch of arrows appeared:
( and upon moving the yellow surface that it appears when you place your cursor inside one of those boxes )
this method works for most parts. but fences and sometimes objects a bit outside the area might not always get picked up by the tool. so remember to clicl CTRL+LMB1 to select or deselect things that you want / do not want
and then, the other important thing last for this small tutorial, is:
how to create Prefabs.
Prefabs are compositions of objects that allow us modders to save specific objects as a group and reuse them in other maps. or clone them instantly through one box opposed as rehaving to do the whole ordeal.
for this example,
i’m going to take a moscow house, and place it into stalingrad ( which is roughly what you will have to do, and want in the first place )
so,
prefab method
first, as covered in the previous section, instance and clone a house ( or you can just selected what you have cloned previously ) or anything that you need:
select the " prefab " next to " toolbox ":
as you can notice, a submenu will appear. now, yours will be empty. but, just click the " create prefab from selected entities "
and give it a name
and hit create.
it will appear in the menu over the left ( which mine is filled as we modders use these quite often )
after that, go back
to the original mod that you wanted these new houses to be, ( in my case, stalingrad )
reopen the prefab, and click twice the item that you saved a prefab of and voilĂ :
due to a recent update, Darflow effed up the doors and windows. so they will not be functional. you’ll have to change their rotation and open them manually through the editor or remove them entirely. GG to darkflow yet again.
also, once you are done with the placement, make sure to hit the " shatter "
button as it will light up the code and make it more server friendly.
and that’s all for today.
once you are finished, you may ask or ping me for more directions
P.s.
as @Devenddar pointed out ( before deleting his message ), it may look a bit scuffed due to not many assets from that time period.
and truth be told:
this might be the only thing you cannot quite do.
reason being, most of the iconinc buildings are one entire piece / set which you cannot modify.
EDIT. actually you can.
the textures though, cannot be changed.
but it’s fine
