Baratako

Olá!
Os LED's fornecidos pela DLC de Special Transports podem ser usados no TruckersMP sem problema. Não será kickado por causa disso.
Simplesmente tenha atenção à regra de save-editing quando começa a modificar o camião usando soluções externas e fora do jogo do ETS2. Se só modificar o jogo dentro do mesmo sem modificações, então não há problema nenhum!
Espero que isto o ajude!
Baratako

Greetings.
Have you installed the 1.34 upgrade for ETS2 via Steam yet? If not, it's vital you do so, also opt out of all available Betas if you're in any.
If you do have 1.34 and "NONE" selected as Beta, then try to reinstall TMP and see if that solves it. I hope this helps!
Kind regards.

Greetings.
All the skills and money that you earn in both singleplayer and multiplayer should still be there when you switch, as long as you use the same profile for both. The downside of this, is if you switch from MP to SP, there's a chance that your truck is teleported to your main garage due to unsynchronized modifications made to your saves, but that is not a huge problem.
I hope this helps! Kind regards.

Greetings.
The problem is the in-game's economy not syncing correctly due to the time in MP always passing by. It's recommended that, in the case you are starting a new campaign, to continue to play SP until you can buy your own truck; this avoids a lot of complications.
If you choose to go for a "multiplayer only" campaign, keep in mind that the late delivery is something that happens on the first delivery you make and it's normal. Also, you will have to sync the economy with MP everytime you log into it, you can do this by sleeping, teleporting to services, fast-travel to garages, or anything else that lets the game fast forward. You can force a economy reset by typing into the console: 
uset g_force_economy_reset 1 Then save the game, reset the game, then load your saved game and then type into the console:
uset g_force_economy_reset 0 And this should reset it and you should be able to see jobs again. Word of advice: don't select any jobs with Caravans on them, unless you are driving a car.
I hope this helps you.
Kind regards.

Greetings.
Each report can only hold one perpetrator per report, so I believe your only shot would to be to create four separate reports. I do understand your concern about filling four report slots for what's supposedly only 1 report, but this is currently the way reports work. If you believe it's a feature that is missing on the website, feel free to post a suggestion about it (if there's no such suggestion, yet). I hope this helps you!
Kind regards.