Sorry I am not so familiar with all the different attack modes of aireplay-ng. I have never tested the fragmentation attack myself, so I can't really help right now. I am going to look into this. Do you know if there is still a mac80211 patch needed (with bleeding-edge mac80211) for fragmentation attack?

Yes, the binaries, patches and source are definitively licensed under GPL. Nevertheless if you are really strict the package also contains some files with unknown licensing e.g. the load and unload script.

You have to use the included custom power kernel (v46-wl1), v46 from the repo doesn't work.

No you don't have to, you can think of it like updating to a new power kernel version.

Yes, all v46 power kernel features should work as usual. There is only a minimal change between the official v46 and the custom v46-wl1.


Regarding battery life:

The problem is not exactly with modules loaded/unloaded, monitor mode on/off.
The main problem is, that if the firmware is loaded the wl1251 chip drains battery. There is only one situation (the most used one) in which the chip doesn't drain battery. When it is associated and wifi power saving is successfully enabled. So in fact there are two states, which doesn't drain battery:
* modules loaded/unloaded + interface down (firmware is unloaded)
* modules loaded + interface up + associated in managed mode + power saving successfully enabled + no additional monitor VAP

This should apply to both, the stock wl12xx driver and the bleeding-edge wl1251 driver.
The included network manager wlancond usually tries to keep the interface down most time, so that the firmware is unloaded. Nevertheless if you "play" with the interfaces and VAPs, you have to take care to put them down/remove VAPs, when they are not used anymore. e.g. if you forget to put your interface down and it is not associated it will result in battery running to 0% within some hours.
As far as I know there can't be done anything against this battery draining, as the chip seems pretty hungry if it is not in wifi power saving mode and wifi power saving only works if you are associated to an AP. (The AP buffers data for the client and only sends at specific time slots. In between this time slots the card can sleep and save battery.)

Regarding multiboot:

Sorry guys, I can't really help you on this topic. I don't use multiboot myself, but as someone got the Neopwn custom kernel working with multiboot I thought it shouldn't be much trouble with the v46-wl1 kernel. I also included the bootimg package, so it should work exactly the same as with the official power kernel.