Yes

It worked last time I checked about a week ago, although adding a second game increased the timer 3 times normal.

yes, you'll need to use the full path. If you idle specific games a lot, you can create a shortcut and add the AppID into the Target field, or create a batch file if you do multiple games at once.

Free-to-Play games were never strictly based on playtime, they always required purchases.

http://psteamcommunity.yuanyoumao.com/tradingcards/faq/

What about free to play games like Team Fortress 2 or Dota 2?
Free to play games drop game cards based on your in-game purchasing. For every $9 USD spent (approximate) since the start of the Steam Trading Card Beta, you will earn one card drop. This card will drop at some point as you play. If you have made in-game purchases in Dota 2 or Team Fortress 2 prior to the Steam Trading Card Beta, or if you owned Team Fortress 2 prior to the Free to Play update, you will have 4 or 5 additional card drops available.

Free-2-Play games do not grant drop just for adding them to your Library, you must spend 9$US for each drop you want.

Open up your web browser of choice and then view individual cookies, how would depend on what web browser you use. You want the cookie for psteamcommunity.yuanyoumao.com/, not psteamproxy.yuanyoumao.com

Double check your Badges page to make sure you have drops remaining. The yellow boxes in this image show what you're looking for.
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=503188239

Free-2-Play games do not give and drops just for adding them to your library, you must spend 9$US for each drop. Non-F2P games give half (rounded up) the number of cards in the set. Trading/Selling/Using those cards will not grant you additional/replacement cards.

Unforseen_consequences lähetti viestin:

I dont know what a command prompt is.

http://windows.microsoft.com/en-us/windows/command-prompt-faq#1TC=windows-8

Unforseen_consequences lähetti viestin:

Somoene said TF2 is 440, but what are the other games' numbers? And how to find out what number I have to write in the ''command prompt'' which I cant find :D

There are a few places, the store page and Badges page would be among the easiest to pull up.
TF2:
AppID: 440
Store: http://psteamproxy.yuanyoumao.com/app/440/
Badges: http://psteamcommunity.yuanyoumao.com/my/gamecards/440/

Portal 2:
AppID:620
Store: http://psteamproxy.yuanyoumao.com/app/620/
Badges: http://psteamcommunity.yuanyoumao.com/my/gamecards/620/

Have you tried running Idle Master as Administrator?