I kinda want to build up an L collection so you guys haven't made this easy on my pockets
An L prime won't help you much in terms of sharpness and color for a studio shoot. In fact, you may want to consider a zoom like 70-200 f4 which is fairly cheap somewhere between the 85mm 1.8 and 135mm f2 and is also an L. A lot of my photographer friends who shoot for big magazines like Playboy use just a 70-200 f4 with their FF on a tripod for studio work. For near the price of a 135L you could buy the 85mm 1.8 and 70-200 F4 and have the best of both range, low light capability, and you'll have an L. For studio, everything else really is just bragging rights. Think about it.
One of my friends used to shoot for Playgirl magazine, and he found that if he need to use his (then) 80-200mm the pictures were never popular
Well, the original post clearly asks for two focal lengths that actually fall into your friend's unpopular range, if you were listening.
He seems smart enough to know what he wants, I'm sure you're aware that distortion from wider lenses aren't normally welcome for studio portraits, editorials, product shoots, etc. I was merely adding the idea of a complete
solution that would give him everything for the price of the largest stretch of his budget. The 85mm gives creamy bokeh from the correct distance, is more compact than the 135mm and is just as good for portraits. It gets the job done. The difference in focal length is also not as big as most may think. Very similar characteristics despite the somewhat better color saturation on the 135L. But you can blur someone's ears away with both
With the 70-200, he'll have that L glass he craves, for industry standard studio work in the most popular studio lengths and the utility for wherever else he might need it. I own, or have owned all of the above. The 135L is a wonderful lens, but you really have to make sure you always have the shooting room from that range on up. It is why professionals designate it as a headshot lens, and a good candid lens for events. With enough room and an unlimited choice of spots to shoot from, it can do everything. Unfortunately that's not how the real world works, so having something somewhat wider around can save you. Also, keep in mind that there is a focus limiter. There's a chance you'll forget about it when shooting a full body shot and coming in for close ups, a mistake that can cost you a good shot. If bokeh is all the OP is really after, the 85mm 1.8 bokeh is quite good on full frame, the 135mm is better, but not 3x the price better. Remember that bokeh isn't everything, lights and reflectors separate you from the typical bokeh look. Any lazy amateur can shoot bokeh all day long. A master of light manipulation will not rely solely on bokeh shots, be versatile. When shooting portraits in most cases, It's easier to move forward than it is to back away. 85mm is a better distance to direct and pose someone from without yelling or getting someone else to do it for you. There is a reason why these focal lengths are commonly designated to specific jobs, they just do those jobs so much better than other focal lengths. Eventually, you'll look for them all.