Do other planets affect the Earth? Let say Mercury, Venus, the Moon were all in alignment between the Earth and Sun. They are all closest to each other in respective elliptical orbit.  On the other side of the Sun you have the rest of the planets. 

Would their gravity combine to have any gravitational effects on the Earth?
Or are they all too far away?
TL;DR: No. Well, yes, but they are negligible.

Full answer: a conjunction like this 'nearly' happened on May 5th, 2000. NASA published an article about this event, stating:

For example, the combined gravitational effect of all the planets together is much less than the effect of the Sun or the Moon on the Earth.

and

While unusual, such alignments have happened in the past without any consequences. The planets are simply too far away to have an effect on anything here on Earth - except our imaginations.

For hard numbers, see this article by Truman Collins which is linked there:

Conclusion
What I discovered was that the tidal forces exerted on Earth from the five planets on the other side of the Sun are vastly smaller than those exerted by the Moon or the Sun. In fact, with the planets in the position they will be in on the big day, the largest tidal force from one of them will be from Jupiter, and it is about one five hundred thousandth the size of the tidal force exerted by the Moon on an average day!