I'll admit that I've never used legacy objects, but record initialization syntax seems to work (at least in {$mode objfpc}):
var
object_2: myObject = (myvariable := 10000);
This works, but there is a slight syntax error, the syntax is like this:
type
TSomeObject = object
a,b:integer;
end;
var
S:TSomeObject = (a:100;b:200);
begin
writeln(S.a, S.b:4);
end.
Note that depending on application my previous slightly complex code can still be beneficial: e.g. if the object has a constructor you need to call it manually.