I got the AG With Mapel Flame. I'd like the grain to stand out a little but not as much as it does in yours. Do you think it's still necessary to ebony timbermate it?
I'd be dubious using grain filler on veneer because of its very thin nature. My concern would be possible sand-through when removing the filler. Also I wouldn't imagine flame maple really needing any "enhancement".
I think I mentioned this in another post, but wipe the veneer down with methylated spirits and it will give you an idea of what the stained grain will look like. The metho evaporates quickly so it won't hurt the veneer or affect the glue.

Also, what did you use as the topcoat and how're you finding it?
I used wipe-on polyurethane that I mix myself. You can buy poly that is "wipe-on" but it's 3 times the cost of making your own.
It's just 50/50 polyurethane and mineral turps.
I wipe it or spray it and it works great. I do prefer spraying it nowadays.