So a lot of info coming, so hopefully some of its of use 
First Off
Your offensive raid team should never be the exact same team every time - you should be building your offensive raid teams based on the specific team you’re facing. For example, if the team you’re about to battle has a lot of buffs, you’ll want a dispeller. If one of those heroes lowers defense, you’ll either want a cleanser, or a hero that raises defense. & If you stack colors, you’ll want to trade out the weak color for a strong color [based on the defensive tank and flanks].
So I can suggest a few good go-to heroes, but not a ‘one-size fits all’ offensive team for those aforementioned reasons alone. Certain heroes work better only under certain conditions, where others can shine in most situations.
Offensive Suggestions (+ Synergies)
Titans:
Red: Wilbur-Zimkitha-Boldtusk-Scarlett/Red Hood/JF [when maxed]-Wu Kong
Blue: Kiril-Ariel-Grimm-Triton/Vela [when maxed]-Wu Kong
Green: Melendor-Evelyn-Buddy-Kingston-Wu Kong
Yellow: Wilbur-Jackal-Leo-Onatel/Joon [when maxed]-Wu Kong
Purple: Kunchen-Seshat-Gafar-Proteus-Wu Kong
Most Versatile: (ie best go-to’s when unsure)
Red: Zimkitha, Wilbur and Boldtusk
Blue: Ariel, Vela, Kiril, Grimm, Triton and Sonya
Green: Kingston, Evelyn, Telluria, Buddy, Melendor, Caedmon and Lianna
Yellow: Onatel, Jackal, Joon and Vivica
Purple: Seshat, Kunchen, Rigard, Proteus, Gafar and Sabina
Best Synergies:
BT + Wilbur + Offensive heroes
Evelyn + Kingston (+ Lianna)
Jackal + Joon
Ariel + Triton + Proteus
Jean + Vela (+Telluria as tank for defense)
Stacked Suggestions:
Depending on your preferred play-style, you may use rainbow, 3-2, mono, etc for offense. I prefer 3-2 or 3-1-1 personally, but that’s just me. If you do stack, be sure to use support heroes as the off-colors, and rely on synergy, or pure fire-power, for the strong color. Usually, you’d stack colors vs whichever hero seems the most problematic [on defense] ie usually the tank and most fearsome flank.
Evelyn + Kingston & Jackal + Joon will be great combos no matter what color you’re facing, as elemental defense down is powerful. Same goes for attack up, and defense down, so utilize those SS.
Defense Suggestion
Stick to rainbow, as it’s the safest bet, while keeping dispels, cleanses, attack ups and defense downs on the left - as the AL moves from left to right
Based on Current Maxed Heroes:
Zimkitha-Seshat-Onatel-Ariel-Kingston
Eventual Suggestion:
Seshat-JF-Telluria-Vela-Joon
Leveling Suggestions
Red: Lancelot and Colen are worth eventually maxing
Blue: I’d suggest making Vela your next 80 project as soon as you get the scopes; wasn’t a fan of her [at first], but now, I love her. Would also take the time to max Mireweave when you get a chance.
Green: Obviously Telluria should see 80 next, then I’d focus on Lianna after. Wouldn’t really worry too much about your other greens [for now].
Yellow: Both Joon and Vivica should eventually see 80, but to start, I’d max Joon first and wait on Viv seeing as you’ve already got Kunchen and Ariel. Plus, Jackal + Joon is one of the best duos in the game. Also, I’d eventually get Chao maxed for more yellow 4* options in WRC
Purple: Sabina and Tiburtus are the two I’d max out of those; healers are always important, along with dispel, and Tibs having defense down is handy too.