There's definitely no Flash player
There definitely IS Flash player.
BUT it sure can't play all the flash files out there (especially games)
But some flash files (Such as Happy Tree Friends) it can play, more or less...
Audio Evolution for OS4 (and ProStationAudio for MOS) are both "multichannel mixing programs". Of course such programs are VERY useful to any composer, but they won't replace a midi sequencer.
About old Amiga sequencers, Bars & Pipes is being developed for morphos, and I think that OctaMED soundstudio is also still under development (Well it isn't sequencer, but a VERY good tracker with midi support)
And of course, then there's also completely new ProTracker being worked on...