Your example lineup is viable and can win depending on which tatic is going to be played and player skill of course. However your lineup is forced to go an all in tactic since it will not outcarry the second lineup.
If they can manage to push one lane of rax around the 20 min mark they have a solid chance of getting another lane and win the game around the midgame. Since they have a solid global ganking strat combined with push it will be hard for the enemies to get a solid early to midgame.
But if they play with mapawareness and defensive they will not get picked of too much and stop the first rax push since they could farm their midgame items on their carries.
So in conclusion: Your lineups are not a good example of extreme cases of lineups and therefore can both win.
There are lineups that are unlikely to win. Those are present in AtoD tourneys (DotA reversed) where people pick the lineup for the enemies (making it extremely bad).
For example an 5 hero lineup with no early game presence like spectre, riki , etc.
Those will most likely not win vs a rounded or a strong early game team.
And to answer your final question: There is no lineup for a guaranteed win if we are talking competitive CM mode. If you are talking about AP there are good synergy lineups but nothing that would not be counterable. Dark Seer + Naga Siren + any more aoe heroes was once considered extremely hard to beat and navi did it with a fast bkb on enigma and an naturally magic immune hero like juggernaut.
Final conclusion:
Picking lineups in CM mode is taking away a lot of the game already. Forcing enemies into tactics that they expect to beat is an extreme advantage.
Personally I found that a great way to improve at the game is to constantly learn new heroes. This gives you a great insight into how different heroes play at different stages of the game, and with different items, along with how they lane in different situations, and who they partner up well with; as well as keeping the game fresh and interesting (variety is the spice of life!)
For example - I kept getting beaten by Axe, so played a few games with him, did ok, and then watched the 'Purge coaches' video where he helped someone on Axe, which improved a) how I play Axe and b) how I play against Axe.
And this is something I now regularly do: get beaten by a hero/watch them played in a pro game, so I play one or more bot games depending on complexity of said hero (i.e. lion/lich - one game. Meepo/brewmaster - 3 or 4 games), watch a Purge video, and then dive into a real game. If I like the hero, I keep playing them, but if I don't, at the very least I've understood that hero's mechanics and playstyle, and over time, this will help you build a strong knowledge of the heroes, their builds, and item use.
If interested, my dotabuff ID is 98862191 "Cjeesebar" - you'll see I'm learning PA just now :) having just finished learning Bristle, LC before him, and WK before him; bit of Brew mixed in there too. Happy to take any questions on this approach.
Best Answer
Heroes still have a damage range, it's just not shown in the UI unless you mouse over.
Here's a useful site that shows the stats in full in a sortable view (show the min damage, max damage, and average damage columns): http://www.devilesk.com/dota2/heroes/herodata