It all depends on the brand and what they wear day to day ... you did not give us any info to go on.
I always say, take a cue from what the managers and staff are wearing, and make it something similar. And take a cue from what they sell ... if it's dressy stuff, you should be dressy ... if it's super casual, then you may dress down a bit. If they sell jeans as a major part of their stock and the other employees wear them, then I think that dressy jeans would be OK. The Converse shoes ... not sure. A dressier shoe might be safer .... unless, they sell really casual, funky/cool stuff and their employees and the managers dress this way. Better to overdress a tad than underdress, IMO.
A suit is not necessary ... unless the employees are required to wear them. I like the idea of a casual, well fitting jacket ... it can dress up a look without being stuffy. Consider nice pants and the jacket you mentioned ... or pop a cute skirt under it with good looking shoes.
You always want to dress for the job you want, just a little bit better ... so keep that in mind.