I am starting to play Dota 2, and I play a lot of League. Which Dota 2 character is similar to either Master Yi or Teemo?
Well, there aren't really similar heroes, but we can compare similar skills between two games.
Master Yi: Alpha Strike is similar to Juggernauts Ultimate.
There isn't hero in Dota with that kinda of heal, where you can stand and tank a lot of any type of damage.
But for other two skills which gives you attack damage and ultimate with attack speed steroid and with immunity to slows Lycan would be most fitting. Lycan has ultimate with makes you run at max speed and is immune to slows, also it gives you critical (covers Yi's passive). Also Lycan has passive skill for more damage and attack speed.
Teemo: His gimick is poison attacks, mobility and 'mines'.
For poison gimick you could pick Viper. He's ranged and has slowing and poisoning attacks and skill that slows opponents if they hit you. (Teemo can run faster - Viper slows opponents :) )
For invisibility and traps - Templar Assassin would be your choice. She can be invisible as long as she stands still and has traps that slows.
But if you want pure traps oriented hero, you can use Techies who are about mines.
Teemo is closest Templar Assassin in Dota. Teemo can stand in one spot invisible forever and so can Templar Assassin. Teemo's Shroom which slows and poison is TA's ultimate which places similar rune that gives both vision and can be detonated to slow.
Master Yi is closest to Juggernaut in Dota. same way to win: you gotta spin to win.
You can't really compare the heroes from DOTA 2 to LoL's champions. Though here is my view.
Juggernaut is a mix of garen, master yi and fiora. Viper is a mix of teemo and twitch. The techies are the closest to teemo because of their ability to mine around the map and cause terrible chaos to anyone who steps on them! The downside is that the techies aren't the "stealthy" type so you better choose which factor is important for you...Stealth or map control?
Another "stealthy" option is Templar assasin, she can put explosives around the map and she can turn invisible. Her explosives need to be triggered though...It isn't an automatic explosive mine.
There is no real hero like Teemo or Master Yi.
Teemo's passive poison is like venomancer poison or Viper poison.
Teemo's blinding dart is like Tinker's Laser. Target gets damage and misses his attacks for some seconds after that.
Teemo's mushroom is like a mine of techies.
All in all Teemo play is like a shitty bastard trying to harass people , so the closest one is venomancher I would say. Spitting your poison and doing more damage then sometimes expected.
Master Yi - pretty simple - Juggernaut - healing ability , spin and of course his ultimate which strike multiple opponents.