Horrible idea!
In the French:
After 1.e4 e6 2.d4 d5 3.e5 c5 4.c3, the Advance Variation, Black plays c7-c5 in 1 go.
After 1.e4 e6 2.d4 d5 3.Nd2 c5 or 1.e4 e6 2.d4 d5 3.Nd2 Nf6 4.e5 Nfd7 5.Bd3 c5 6.c3 Nc6, Black plays c7-c5 in 1 go.
After 1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.e5 c5, Black plays c7-c5 in 1 go.
I think you get the gyst here. You are losing a tempo every time White plays the French.
As for the Dutch, there is no stonewall dutch against 1.e4.
I don't think you get the point behind either opening.
Dutch: Prevent e4 as long as possible. After 1.d4, there are 3 ways to prevent e4 by White, 1...d5, 1...Nf6, and 1...f5 (The Dutch). After 1.d4 f5 2.g3 (The f-pawn blocks the Bishop on c8, so White prevents Black from getting in b6/Bb7 first) Nf6 3.Bg2 e6 4.c4 c6 5.Nf3 d5 6.O-O Bd6. Notice White STILL hasn't gotten in e4. After 1.e4 the Dutch is OUT!
French: In the French, after 1.e4 e6, Black hems in his own Bishop on c8, so to counter that deficiency, Black needs to act fast. The White pawns end up fixed on the dark squares, and Black has a fixed target on d4. He needs to play c7-c5 in 1 go.
Now I know you are going to argue that the Caro-Kann takes 2 moves with the c-pawn, but in return, Black hasn't hemmed in his Bishop. The French is a more rapid counter-play by Black. The Caro-Kann is slower but less committal.
Don't try to re-invent the wheel and instead play something normal that follows opening concepts. After 1.e4 e6 2.d4 d5, White's e-pawn is under attack, and he must either Protect it, Advance it, Exchange it, or Sacrifice it.
After 1.e4 e6 2.d4 c6?, Black has done NOTHING and White is free to do whatever he wants! Large Advantage White already!
What's your "friend" rated? 1200? If you are listening to a 1200 player for advice, that's your first mistake!
My friend showed me this opening with which I am not that fluent. Can you guys rate it please? When white plays e4 black plays e6 then no matter what white plays after that black plays c6 and the game either goes into a french line (exchange, advance, etc) or transposes to a stonewall dutch line. What are your thoughts?
Thanks