Even N900 doesn't lag with such a load, I wonder where did you get that one from. Maemo5 uses about 270MB with TMO and Facebook opened in microb, with media player playing in background and conky opened. Just tested that. And I can tell you that N900 opens various applications(contacts, conversation, phone, etc) faster that galaxy S4 mini. Draw your conclusions. If you can.

On N900 there is very little (if any) difference between device running on 600MHz and 805MHz. Assuming you put a sane load on it.

And honestly, after all those years I still don't grok why it is acceptable for my desktop (4 i5 cores, 16GB RAM) to need 5 seconds to load firefox (for example), but the same 5 seconds are not acceptable for my phone. That's perverted, sorry.

For various reasons already explained countless number of times in this very thread.

Also, for OMAP3 we can reuse GPU drivers from N9/50, the same goes for DSP codec nodes. Tested and tuned by Nokia for production devices, not the crap TI distributes on their webside.

Because all devices besides N900 are either with locked bootloader or lack too many features HW wise (or both) for someone to be interested in porting Fremantle to them.