Gain for the sake of gain it's not helpful. For quads (to be your body friendly to them) what you need is your mass to be distributed as close to axis of your rotations. That's why we don't see many male skaters to have "manly" wide shoulders and strong muscular quadriceps. What prevails is as you mentioned body types like, Yuzuru, Nathan, Boyeang etc. Triple axel is partly an exception because of forward take off.
In Alina's case the gain can be done having in mind some loose later. You get more muscular because you want to increase the height of the jump. You change a bit your muscles qualitatively and in mass. Then when the time will come for the actual training for quads (if that's the goal anyway) you will start to loose some, to adjust the rotation. All this in parallel with necessary changes in technic of rotation, leg, arm position etc. In Alina's case, she is not pre-puberty any more, you cannot (the way I see it) achieve the big jumps by just loosing weight an bringing your mass distribution closer to axis. Rely only on speed of rotation. A lot more work needs to be done in many directions.