1) Yes, it is possible. With the integration of AirMod into the official source, you can define alternate firing modes for weapons. However, with stock AirMod, you cannot define which key is used to enter the alternate state. To do it with stock AirMod, you press the number for that weapon again. So if the weapon is in slot 2, you press 2 to equip the weapon, then press 2 again to swap between alternate firing modes.
But, with Project Blue, you can create a weapon script and define your own keys for entering alternate firing mode.
2) With Fenix Mod, there is a way to set up melee attacks with weapons. I haven't used it myself, but others have said that it's a good feature. I am not sure if it will be going into the official versions or not, but there is talk of it being integrated into the official source at some point in time. After all, the creator of Fenix Mod is working on the official versions now. On top of that, he is also working on Project Blue, so at some point in the future it may be available in that Mod as well, alongside weapon scripting to make it even more dynamic and customizable.
Hope that helped.
The one and only,
