====<SMOKE GRANADES>===
Basically it requires some file editing but not too hard
First, you need to create cannons at slight angle (use Ctrl+D to , short, 50ish caliber and breach doesnt change anything, then add ammo, and crew to operate( all lauchers can be assigned to one gunner, and loader IF you want them to shoot only once)
If you did this step u need to save your prototype and go to files (You can do this by going in-game into paint and custom and add, then get back in documents) click factions, click your tank faction and you can search your design, click on it (you can open it by notepad or notepad++, like me- its easier to search and edit for me) and look for "shellSlot", it will look something like this:
"id": 45,
"type": "shellSlot",
"blueprint": {
"v": "0.0",
"name": null,
"description": null,
"diameter": 50,
"propellantLength": 30,
"generatedProjectiles": [
{
"projectileTypeGuid": "26b92ec4-b740-42a4-aeb3-12ff61463b82",
"functions": [
{
"id": "AP",
"definition": {
"penetratorConstant": 1600
}
},
{
"id": "Propellant",
"definition": {
"length": 30
(some values might differ because of used era)
below "penetratorConstant" you need to add
}
},
{
"id": "HE",
"definition": {
"delay": 0.1,
"explosivePower": 50000.0
Its HE filler, so u can use this on normal guns
if you did everything correct your smoke granades should work!

====<STABILIZATORS>===
Instead of gun mount (mantlet) you need to use turret on its side and add a cannon to it, also modify torque to max value - even with file editing (search turret, motor and change torque to 20000 (i think its max value)

====<ERA>===
well its more decoration than working, but better than nothing
you only need fuel tanks, u can use barrels but they do sh*t, but if you use boxes you need to make sure that they dont collide with your armour - a shell would go thru fuel tank and ignore armour, so u need to leave (very little) space between them
well thats all!
(I could add some more photos and videos but im just too lazy to do ts)