in short,
low upgraded sabateur drone will drop only 4 mines, while high upgraded sabateur drone will drop 8 mines and there is the drone cooldown which is the same as mine cooldown 30 seconds. If you place a mine using the drone and then you get destroyed then you get respawned, then you can only drop one mine because the drone is in cooldown.
This drone is good if you have good team defending you cuz placing mines makes you the weakest link, players will target you very easily to get rid of the mines. Use miner drone, much more effective and less cooldown time. 

Thunder > Tesla > Viking > Hopper

If you participated in the Tanki fund, then you will get the OP augments for Thunder and Tesla. Viking is powerful. Hopper is good, but it will flip very easily nowadays. 

No-damage bug is common, the only solution is to refresh the game. This bug occurs due to high ping sometimes or due to the anti-cheat system

Strange bug, happens often, no new info.....
The only way to correct this, you have to pause and unpause the game. Then you will regain control of your tank

If you have video evidence to support this, then you can submit this strange bug on the topic "Bugs and glitches report" in the forum itself
Try playing in different platforms, for example - if you playing on client, try playing the game in browser and see if the same problem comes over there
SGE is not about getting kills but also capping points, people who cap the points will earn more score
 
 
No-damage is bug is common, only solution is to restart the game - happens when you experience high ping. 
Sometimes, the enemy has higher upgraded turret/augment equipped/assault-type drone equipped  which can can easily destroy tanks in one shot regardless of the protection sometimes. Sometimes, you might have been affected by the AP status effect (Armor-piercing) which destroys the protection module and double armor for a short period of time. If your hull is low-graded, that can also be a factor

Transferring items between accounts is not possible and in my opinion - should not be considered.
Because, lets say you get crisis in your alt acc after the tanki fund. Someone hacks your account and he/she might send items like crisis drone to his/her own account. You cant even recall any items, if you do your own account will be blocked for breaking game rules.

Make sure to have this option disabled : 
If this option is enabled, then you wont be able to visit your profile from the ratings page

If you mean the stars contest, there is one going on. Top 10 players will get scorpion turret and the top 100 players will get 100 batteries. You have to earn stars in battles in order to reach the leaderboard.
As for the Contests which is organized by the helpers, it has been closed for a few months now. Reason for its closure is unknown. 

It takes approx 1 week for the reward to be sent to the QOTW (Question of the week) winners

You will need a password to enter the forum and other tanki sites since google cant help you there.
One way is to obtain a password is to visit the game settings and click this :  
You will be able to obtain/create a password for your linked account and you can use this anywhere related to tanki domain sites. This method will help you to skip tech support's response and waiting time. Advisable to try this method before approaching tech support. 
 
If you are unable to recieve a password for the account, then you can contact tech support for solutions... (help@tankionline.com)

Link for Youtuber wiki page : https://en.tankiwiki.com/Youtuber_TO_Program?attempt=2
Note: Only views tanki-releated videos will counted in that site. 

Current maps in Tanki : https://en.tankiwiki.com/Maps
Mapviewer tool : https://en.tankiwiki.com/MapViewer