Launch screen and icon dimension issues and confusion in ios 7 and 8

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Mobile

iPhone

iOS

iOS7

After a lot of mess I am finally asking regarding the splash/launch screen confusion of iPhone and iPad. I visited many links but couldn't find an appropriate answer for that. I want the dimensions of iPhone and iPhone launch screens. Currently what I did for for

iPhone
Default-568h.png (320 x 568)
Default-568h@2x.png (640 x 1136)
Default@2x.png (640 x 960)

I used these three dimensions and they are working on all iPhones(from 4s to 6 plus). But there is a launch xib now provided. So whether this xib will run for the ios 7 or not?

Now if I use these two dimensions provided above for 4s, 5 and 5s, no doubt the 640 x 1136 is also applying in iphone 6 and 6 plus, but there may be some pixel blurring in launch of iphone 6 and 6 plus. Can anyone provide a generic way for launch screen for all devices (4s to 6 plus) with ios 7 and 8 support too.

iPhone 6 and 6plus
6+ (1242x2208)
6 (750x1334)
Question:-I know these dimensions are used for iphone 6 and 6+ but what will be the name of .png for these two devices just like we used Default-568h@2x.png etc for other devices if in case we don't use launch xib.

iPad
Default-Portrait~ipad.png (768 x 1024)
Default-Portrait@2x~ipad.png (1536 x 2048)

Similarly for landscape
Default-Landscape~ipad.png (1024 x 768)
Default-Landscape@2x~ipad.png (2048 x 1536)

Question:-Is any other dimension is required with some other name?

ICONS
I used to to do entry in .plist with Icon Files and the dimensions are
29 x 29
40 x 40
50 x 50
56 x 56
57 x 57
58 x 58
60 x 60
72 x 72
76 x 76
80 x 80
100 x 100
114 x 114
120 x 120
144 x 144
152 x 152
512 x 512 for iTunesArtwork.png
1024 x 1024 for iTunesArtwork@2x.png

Question:- I listed almost all icon dimensions are but What will the the minimum number of icons that I need for all iphones (4s to 6 plus) and iPad? How many icon dimensions can I disgard from the above list. Any help will be appreciated in clearing the confusion.

Thanks