My understanding is that Android "multitasking" will work just as on any Android phone, that is, Android will continue to multitask whatever is coded as a service, but if you run a loop on a terminal within Android, that won't multitask, unless the terminal is hacked in such a way that is, well, not a terminal any more :-P

In addition, Android can only render one application at a time, so don't expect a lot of them to be shown in Sailfish's multitasking screen. It has been requested to modify this behaviour in the ACL, but it has also been challenged as there is no point in wasting effort to improve Android's compatibility when you can use it to improve Sailfish itself.