Of those that you mentioned, Shen and Lissandra are probably the safest to play for top and mid respectively. Lissandra is good in solo queue due to her pick potential, semi strong laning phase, mobility from claw, etc. She's relatively simple compared to the other champions that you listed, but still strong. Shen's more team reliant but he can solo carry if you know how to play him well and get your build rolling.
If you want to play Gangplank, I suggest watching a few pro players play him. He has a really high skill floor and ceiling, so be prepared to put a lot of time in mastering barrel chains and matchups. He's a type of champion that it is possible to bounce back if you have a bad early game though (Q gold, ult to help in teamfights, just general high damage once you get core items)
Twisted Fate...is something I do not suggest to lower elo players, no offense. The issue with TF is that he requires pretty damn good mechanics, positioning and map awareness even if it doesn't seem like it. If you'd like to learn him, I'd start in normal games, play 50 or so normals with him then you can try to go into ranked so that you can learn ult timings, card picking, when to split, etc. While a good TF can very easily carry a game, a bad one can honestly lose you the game.
As for Syndra, she's a fun champion to play and she does pretty well in lower elos due to the fact that a lot of people underestimate her damage (especially from her ult) so you can carry games if you get ahead. However, you do have to keep in mind that if you miss your combo, you're left vulnerable. Keep in mind that if you can't get rolling on her, she may seem like a feast or famine type of champion.
Bard is one of those champions that's really satisfying/rewarding to learn and master, but imo he required a decent amount of games otherwise you can screw your team over with Magical Journey/Ult.
Swain/Ryze are both extremely strong but are pretty common bans right now, so I'd probably hold off on playing them. Ryze also seems to get reworked like every season so...yeah.
Overall it seems like you chose rather difficult champions to main...lol. It isn't bad, but just keep in mind if you plan on maining those champions you listed you may want to put a few hours into playing them. Learning a hard champion and mastering it is always fun and challenging when you finally succeed and reap the rewards for it. Apologies for the long post. Good luck on the rift~