Well, if a 3rd party team would start, and get something working, in time it might be merged back. Actually with pas2js Lazarus supports already 2 "compilers".
But from within Lazarus I don't expect such initiatives.
And that means just IDE with an own written designer for C++, or adapt a C++ compiler to generate relevant RTTI. Borland enhanced their C++ offering too to get it up to the level of Object Pascal. Specially and RTTI, enum sizes etc.
And then still the pascal code needs modifications ({$externalsym xx}, .hpp headers written for them). All possible, but not an easy project