Ya you will accumulate enough electric shells for the shotgun to keep 1 person supplied with them, providing you use burst very very sparingly. And solid slug shotgun ammo is modestly effective vs the bots.
Hmm, fast shot when using rocket launcher...I'd vote yeah-it does enough exlposive damage to kill most bots in 1 to 2 hits so you really don't need to be hoping for criticals on aimed shots. Also, one thing you definitely don't want to use rocket launcher except at long range-sneaking up behind some enemy with the rocket launcher is kinda suicidal.
Everyone may say you need energy weapons late in the game but heavy weapons are just as effective and usually more so-at least the browning m2, rocket launcher, gauss minigun (for all of the 20 shots you could get with it), and vindicator mingun (with good criticals/a vodoo) are much better than single shot energy weapons. browning and guass are better than the gattling laser, and rocket and vindicator aren't horribly below it. Also, the pancor jackhammer (shotgun) with solid slug or electric shells, the guass rifle, and the 40mm grenade launcher are small guns that are effective against robots. You don't have to use energy weapons against robots at all, but they are definitely a good (though not the best) choice.
Also, just be aware that equipping power armor is gonna send your sneak skill to hell (-75% IIRC). Personally I've never been a big fan of sneaking-mainly just a waste of time imho, especially when even in Quincy (the best mission for sneaking in the game) you can do virtually every bit as good just by quick but careful and planned actions. But if you wanna be a sneaker thats up to you.