Best Team Comps

You can pair Waver with anyone, for farming pair him with any Aoe servant, boss killing with any ST servant. You may prepare some low star servants in your party like Hans, St. George, Cu, Medea, etc, even Mashu, they'll help you a lot (and for better team cost effectiveness)

Right of the bat, like my fellow player said, you have Waver, and he's just plain awesome. Although as a AAABQ, one might not think of him pairing best with a BBBAQ Berserker like Herc, I think they could actually work really well together. Herc has an extremely strong Noble Phantasm for clearing out entire waves, however, his card set makes gaining NP difficult for him, a Waver combined with any NP gain CE (Kaleidoscope preferably but if not I think the 4* version is called Imaginary Element which is also really good) can allow him to have NP right away.
Saber Alter is also a wonderful servant (legit between her and Herc you have the two best 4* units in the game right now...actually looking at your list all of your servants are the top of their respective tier levels). Excalibur Morgan is one of the best NPs in the game and her kit also builds around it. Since her deck is AABBQ, she definitely pairs well with Waver since he can provide tons of nice juicy Arts chains for her to gain NP from, allowing her to charge up her Excalibur Morgan quickly. Salter and Waver are basically the ideal offense oriented NP duo.
So yeah, always run Waver and Salter together. To be honest, Herc kind of messes with that synergy by only having one Arts, but well, Jack only has one arts too (I'll get to her in a bit), and like I said, Waver is the key to unlocking Herc's potential (admittedly he's the key to unlocking anyone's potential).
Now Jack. Like I said, you really have the best of the best servants in this game (at least until Merlin makes everyone else pointless). Jack is without a doubt the best Assassin. She's the ultimate crit star generator, and can get 50 crit stars (100% of crit on every attack next turn) just with one brave crit chain. I'm very proud of my own star generator in Okita, but I admit I still wish I had a Jack to be friends with her (luckily Shiki and X are providing her plenty of help in the meantime). The biggest problem with your jack is that while Jack is good on her own, she's best with friends. Having other units with at least two Quick cards in their decks are really preferred for a crit team, which your Jack is the dream core of.
Still, just from Jack's power level, she can still go with the others, she just doesn't have specific synergies with them (although we've established Waver goes well with everyone, she'd be better with a team specifically tailored to her even if it includes Waver). Ultimately, however, I'd suggest taking other three as a front line, and then boosting the back line with some Arts heavy presence: Hans and Mash are two of the best support units in the game and they're both arts oriented, but if you want something a little more offensive focused you can take out one for a Medea. You might even want to put one of these units in the front line with Herc in the back to provide a last ditch effort mega NP assuming you can keep Waver alive to also be there when Herc comes up.
As for Jack, like I said, you can still put her in with the rest if you like, but she wont be at her max potential. Try putting her with some lower rarity quick focused servants. I'm not sure how recently you started playing, but if you did get Shiki from her event last month, she goes perfectly with Jack. Another good option might be Cu because he is one of the best 3* lancers and has two Quick cards. Other quick oriented characters that are top tier in the lower rarities include Robin and Hassan of the Cursed Arm. None of these units of course are quite at the sure level of firepower that Jack has (well Shiki's pretty amazing), but it's with such a team that Jack will have the tools to more or less decimate any enemy she so chooses.
If you want to know what servants to aim for in the future, I know saving for her is basically a meme by now, but Jalter is an incredibly powerful offensive servant with two Arts card that will work extremely well in your offensive arts deck, and really, most Saber servants have the exact same card deck build (AABBQ) combined with a really powerful noble phantasm (Nero works especially well as she has an Arts NP). The exception to this is Okita, but she wont be back in a while, and she would actually be your Jack's best friend anyway as the second best star generator in the game so you'd want that.
Absolutely anyone would tell you to try for Merlin. He's just the best. Hands down. He also has a triple arts deck which goes well with your Salter and Waver, but you know, it hardly even matters what your comp is with Merlin (that might be a little bit of an overstatement but only a little).
As for what friends you want to summon for your Jack, I already mentioned Okita (but its a long time before she's available to summon again). Really almost any gold assassin would work well with the exception of Stheno...like...technically she still provides Quick cards, but...its hardly worth it. Scathach will be having a rate up pretty soon during the mid-summer, and she's a top tier lancer who has two Quick cards in her deck. Just really, if you see a 4 or 5 star lancer, archer, or assassin, they're probably worth considering because any high stat unit with at least two quick cards + Jack the Ripper = your enemies are already dead.

Umm...I didn't really realize how long this thing got...sorry about that...I do tend to get carried away:
tl;dr Herc + Waver + Salter + other arts cards
Jack + other quick oriented servants
Save for Jalter
Scathach is also pretty cool
bye