Hello @Coke, welcome to the game
You have made a good start, but your question about tabards suggests you need to learn some fundamental ideas about making progress in the game.
Before making decisions, read through some of the player guides.
I suggest starting here:
Read through some of the links in the first post.
You have been very fortunate to pull lots of good heroes early on, but your 4* and especially 5* will probably take months to level up fully.
My advice, unless you are planning on spending multiple hundreds of dollars/euros is to level up one of every 3* hero first (I play completely free). This is a foundation to then collect the materials you need to progress.
This seems counter-intuitive as you have stronger 4* and 5* but they demand huge amounts of 1* and 2* heroes and food to level up and this will slow down a balanced team.
3* are useful for war and quests well into the game, so it’s not a waste.
If you are not yet in an active teaching alliance, I recommend finding one.
Lots can be found here, but there are lots of others:
Specifically on the question of tabards - you don’t need any - Sabina needs trap tools and Lianna needs shields and tonics.
These cannot be found during levels, only rare quests, events, titans, raid/monster/titan/war chests, mystic vision and some paid deals (but these are often random or poor value).
They are rare, being in an alliance, fighting wars, beating titans and completing quests and events is your best bet.
The game rewards dedication. It is fun, social and more nuanced than it appears; but it is a long term grind and there are no short cuts.
Enjoy!