Given that most of my threads about concept games usually feature someone saying "make a game already!", I've decided to do just that (one's portfolio only gets so far with concepts, after all).

That being said, I have two engines already on a computer suitable for work.

Option one is Unity. Option two is UE4. Part of the advice I'd like this time is which engine is easier to learn how to use and to actually make a simple game on?

As for the game itself, it is either going to be:

1. a breakout ripoff, possibly featuring a large beetle as the "ball".
2. a game in which the player must cause all but 1 out of four racecars to crash within the race. There are pre-determined scenes that are switched between on a timer. The player has a limited amount of time to cause a crash by triggering environmental hazards at the racers; these hazards are dependent on the current scene. The player is scored based off of how many hazards it took for one car to crash (the more hazards the higher the score), how late in the race the crashes were caused, how innocuous the crashes looked, and how late in the race the car was as it crashed. The player is not scored if they caused the designated car to crash or if any of the cars did not crash by the end of the race.
3. A rail shooter, featuring three characters: a British explorer, an Ottoman hunter, and a Sudanese soldier. each has their own special abilities and weapons to use against the various enemy forces in a level (ranging from bushwackers to wild animals to demons), such as the explorer's elephant gun and survey scope, the hunter's bow and dual pistols, and the soldier's broadsword and talismans. While the player is waiting in between levels, they may spend money earned from defeating enemies to upgrade their abilities and passive stats. Special boss battles allow the player to gain access to new abilities.

The genres are all listed in terms of difficulty to create. It's actually a planned set of three games; whichever seems to be the easiest will be my first.

It's all something I literally just thought of, but simple games like the aforementioned breakout clone where the player bounces a Goliath Beetle into a wall really don't need months of forethought.

Other major questions:

1. Distribution: I've heard Kongregate and IndieGoGo have a couple caveats regarding distribution (namely that the former is small and the latter is restrictive). I'd also like to know of other good distributors for simple indie games.
2. Time: I plan to have one game out in about 6 months. This may seem unrealistic for some of the concepts, though. I'd like a very basic run-down on how long it takes to create something like the games i just mentioned.
3. Cost: I plan on using largely pre-made assets for these games, so I'd like budget estimates so I can plan which assets I have to buy or create.

This question is a matter of opinion. i also agree with fleabay, a good graphics engine( threeJS/irrlicht) + a physic engine(bullet) should be enough for these simple games, but that's if you want to roll you sleeves up and learn some stuff.

You don't have 3 choices. You have 1. The Breakout clone.

As for the engine, don't use one. It's too simple. By the time you learn the engine, you will be halfway through making the game from scratch.

You can find Pong tutorials for just about any language, consider using YouTube as an option. A Pong tutorial should give you just enough of a boost to create a breakout clone, or at least get you 99% of the way.

This does make complete sense anyways. I do have a bit of a tendency to overthink things.