first one don't know if it's a manga but the art it's from tateno makoto; second one, i don't know, sorry...
Sorry i hadn't seen the other links, anyway i don't know either
The first one is not from tateno makoto, it was actually drawn by tohjoh asami(it says it at the bottom of the pic in tiny font)but unfortunately she had passed away. I don't think it is a manga, but if you want to read some of her works l, try reading Love Prism. Don't know about the second one tho.
I think all of those are just illustrations. But all of the authors are written with small letters at the bottom of the illustrations, so you can check mangas from them
the 1st one i think is this
http://www.mangago.me/read-manga/thunderbolt_boys_excite/
2nd maybe this one
http://www.mangago.me/read-manga/heart_o_nusumu_no_wa_dare_da/
anyone knows these mangas????
http://www.mangago.me/read-manga/mumyoutou/mf/v01/c001/2/
http://www.mangago.me/read-manga/mumyoutou/mf/v01/c002/
http://www.mangago.me/read-manga/mumyoutou/mf/v01/c003/
http://www.mangago.me/read-manga/mumyoutou/mf/v01/c004/
http://www.mangago.me/read-manga/mumyoutou/mf/v01/c005/
http://www.mangago.me/read-manga/mumyoutou/mf/v01/c006/