You didn't get my point. Currently(and for atleast a year from now) Lazarus uses static packages.
That is: Packages are compiled "into" lazarus which is then ran again.
This means that anything platform specific in the game-edition package will make lazarus with it also platform specific(linking).

It could be done by dynamic linking but you'd need a dynamic pascal header for DirectX for that.(+ other hassle)

As for FPC/Lazarus's qualities well, to be honest(note: I do love FPC and Lazarus) it has not much others. It's slower than Delhpi(version dependant), has lesser components than Delphi, more bugs than Delphi etc.

If I was developing in windows I'd use delphi unless my budget or other circumstances(like my love of opensource) forced me otherwise.

I am, however developing cross-platformly

I think a good definition of "game edition" is in order too.
Perhaps it might be best if the package was configurable in some way so you could choose backends. This way many renderers even platform specific ones could be included and will be available to choose on the given platform only.

Even in simpler form this is a helluva work. If you're not thinking one platform only the testing and polishing required(not to mention making the design good, getting GLScene and others working etc.) will be extreme

I'm looking forward to it