Great analysis! Thanks for taking the time to explaining your findings in detail.
I've been running double Firesprays almost exclusively for the last six months and it is reassuring to learn we have both come to broadly the same conclusions.
Boba with Maul crew is amazing. At range 1 of an enemy the re-rollls and Force mean your damage and defence dice are consistent even if you don't get an action. Personally I like to add the Slave 1 title to give me options during activation. It makes the ship harder to predict and more flexible, doubly so because of being able to take shots from the front or rear arc.
I have been using Emon for a long time, and love the way he can play with bombs. Add the Andrasta title and Delayed Fuses and it is possible to really cause trouble for the enemy with your Protons and Prox Mines. BUT, like you, I don't think Emon is good enough in combat. Even with Perceptive Copilot enough damage isn't pushed through. A player with experience against Emon can work around the bombs - even sacrifice a shield or two - and cripple him with a round of focused attacks.
As an alternative to Emon I have tried Krassis with Cluster Missles and had some success, especially against mini swarms. But as you say, the lack of defensive mod also means that Krassis gets hurt badly by concentrated fire. I haven't tried Snap Shot on Krassis but my rough maths says it will be roughly as effective as Dengar gunner, but Dengar is a simple 50/50 roll on a red dice, not a bonus attack, so has the same odds whether against a 3 agility ace or 1 agility hulk. Also Dengar and a Cluster Missile bonus attack can trigger in the same turn, but not so with Snap Shot and Cluster Missiles combined.
Personally I haven't had much luck with Koshka Frost. I haven't been able to get her ability to trigger consistently and I have found this frustrating. But also I haven't tried Rigged Cargo Chute so that is now on my list. On Koshka I include Marauder title for an offensive mod out the rear, along with Dengar for some some bonus damage output.
Finally bombs or mines are essential on both of the Firesprays. Protons, Seismics and Proximity Mines are all excellent and have strengths against different lists. For Boba I prefer Proxies for the chance to dump 1-3 damage on an enemy ship and get immediate results. It pairs well with the Slave 1 title and I get good results with this combination in almost every game. Protons are my choice for the second 'Spray, using them to hurt swarms or corral aces.
Thanks again for sharing your insights and you have convinced me to give Koshka more table time.