Your gear sounds fairly sufficient for soloing U4 and U5 (though I would avoid U6 until everything is fully pearled and forged to shadow level 5.) Prioritize getting a full set of Shadow Level 5 pearled before working towards any Radiant items.
As for stats, I strongly recommend ensuring you have HP and %HP, as this greatly increases your survivability. Tomb Raiser and Gunslinger have fairly polar stat priorities (Gunslinger wants Attack Speed and Magic Damage; Tomb Raiser wants no attack speed and a lot of Energy Regeneration.)
Alright, great! Both sound fairly good in terms of emblems/flasks/allies, though they could obviously be optimized further (granted, it depends heavily on personal preference.)
My first piece of advice, is to invest in the Bandolier flask (unless you have crippling lag issues and cannot use flasks in time as a result.) The Bandolier flask generally allows you to use your emblem effects 1-2 times per battle, and you will rarely run out of flask doses before you need to return to a Cornerstone to deconstruct your treasure. This is a massive boost in your power, as you can effectively maintain a constant 2X damage boost and secondary effect.
Having said that, I'll delve into each class separately now.
I strongly recommend getting your hands on a Chronomancer Qubesly if possible. This will increase your damage dramatically, especially when using the Arcane Emblem boost. A secondary option is a Prowling Shadow ally (generally a universally viable ally even if not optimal on all classes), as Gunslingers tend to have a lot of attack speed and the healing can greatly offset any damage you are taking. The Prowling Shadow makes the game a lot more forgiving for you, which can be important on a Gunslinger if you have not yet perfected the art of aerial combat/avoiding damage from enemies (once you have honed this skill, pure damage is much more effective than healing.)
Your Vampiric Emblem is a similar case to the above argument of Chronomancer vs Prowling Shadow. The healing will help offset damage you take (especially once you have a Bandolier flask), but if you can get to the point where you rarely take any damage to begin with, then the Sorcerous Servant Emblem may be superior for you as it deals quite a lot of extra damage (especially with an Arcane Emblem.)
You were on the right track in valuing Energy Regeneration so highly on the Tomb Raiser, as maintaining a high up-time on Banshee's Boon is essential to building up your minion army/grave goliath (as well as mitigating a lot of damage whilst standing so close to enemies.) Having said that, You may wish to reconsider catering your emblem and ally to it. The Feisty Flamedancer provides a 12% boost to energy regeneration, and the Energetic Emblem provides a 50% boost to energy regeneration. Since these are percentile boosts, they rely on your base Energy Regeneration being high in order to really shine. If you do not already have a lot of Energy Regeneration (which, with shadow 4/5 gear that is not fully upgraded, you likely do not), then the boosts from these effects are severely diminished.
I would instead recommend perhaps replacing the Energetic Emblem with the Vampiric emblem as well for the time being. The Tomb Raiser receives a 27% boost to its maximum HP, meaning you will naturally have a higher HP pool and benefit more heavily from the 10% (I thought it was 2.2%, but the wiki says 10%; may need to verify this) of your maximum health being restored on each hit you deal to enemies than you will from having Banshee's Boon active slightly more often. Likewise, I would also recommend replacing the Flamedancer ally with a Chronomance Qubesly or a Prowling Shadow (depending upon how comfortable you are healing-wise; sometimes more offense can be stronger than stacking defense.) The Prowling Shadow and Vampiric emblem combined generally result in you being nigh unkillable (especially once you activate Banshee's Boon and trigger the healing off of all enemies, whilst taking 90% less damage.)
Gunslinger: Get the Bandolier Flask, replace raptor with Chronomancer Qubesly (possibly Prowling Shadow alternative), Practice Aeriel Combat and Avoiding damage, possibly replace Vampiric emblem with Sorcerous Servitor.
Tomb Raiser: Get the Bandolier Flask, replace Flamedancer with Prowling Shadow (possibly Chronomancer Qubesly alternative), replace Energetic Emblem with Vampiric Emblem.