It's a 'port' and therefore will be problematic.
Except for the official Google ones every device is using a 'port'. The CM maintainers even have to port the latest code back to the older official devices (as was done with the N1 long before Google engineers pushed the changes to their public Gingerbread repositories).
Leave Gingerbread for Scorpion based devices that actually can run it smoothly due to a faster processor and more internal memory. 90MB for application memory isn't enough.
I just checked: At the moment I've got about 150MB of user memory available. Keep in mind that my system is up and running for a few days now and that Android keeps processes in memory until it has to free some for new ones.
I dare to assert that my knowledge concerning hardware support, hardware requirements and Android ports is quite profound. I may not have been as deeply involved into merging the CyanogenMod codebase with Gingerbread as say Cyanogen back then, but I nevertheless know a lot of code well enough and I also created the CPU/arch target for the Legend locally to build and run my and the World's first Gingerbread port of Android on my Legend. Said target was later added and merged by Ricardo Cerqueira by the way.
I also dare to state that the vast majority of differences that could seriously influence performance is to be found between Éclair and Froyo and that those differences resulted in nearly doubled scores in benchmarks. Even if you don't "believe" in benchmarks (I certainly don't) a 100% plus should at least prove that the Legend if perfectly capable of running Froyo. Because the differences between Froyo and Gingerbread are so small and cover a vast majority of completely different areas (like getting rid of a lot of legacy code) Froyo and Gingerbread are quite close.
You might be using valid English – which is not worth mentioning for a native speaker anyway – but that makes your false pretences not a whit righter.