Salamun Alaikum,
The word 'alladhani' in verse 4:16 is a masculine dual pronoun which most likely refers to two men which is further supported by the context of the previous verse which refers to women (4:15).
Verse 4:15 is addressed to women indicating three or more, by the use of the plural pronoun 'allati'. This is unlikely a reference to two 'lesbian women'. Therefore, 4:16 has nothing to do with verse 4:15 which is referring to only two people (dual).
Thus, 4:15 is possibly a reference to such women that cause 'fahisha' such as prostitutes etc.
Once the subject of women is dealt with in verse 4:15, the attention then turns to men (4:16) indicated by the use of the masculine dual pronoun.
4:16 is not a reference to illicit heterosexual relationships as that is dealt with in 24:2.
Furthermore, relating the duality of 4:16 to the plurality of 4:15 (women) makes no sense. Therefore, 4:16 with the use of the dual masculine pronoun is most likely a reference to two men.
There are other verses which address homosexuality in context of the community of Lot (pbuh) for example:
026:165-166"Of all the creatures in the world, will you approach the males (dhukrana), and leave those whom your Lord has created for you to be your mates? Nay, you are a people transgressing (all bounds)" Please also see related posts on the subject from the site:
[1] Is Homosexuality Punishable By Death?
http://quransmessage.com/forum/index.php?topic=79[2] Tattoos and Homosexuality
http://quransmessage.com/forum/index.php?topic=65[3] Rape
http://quransmessage.com/forum/index.php?topic=314I hope that helps, God willing.
Regards,
Joseph.