You got 6 cards last year. Let them age at least a year and build up some history. I wouldnt app for anything this year. Let the 6 hits to your CR age as well. You have enough cards for now to show the big guys that you can handle that many accounts and be responsible. If any of them have a fee yes. If not. Keep it for now. You can ask for a CLI after 3 statements with Cap1 and still get a CLI with the Credit Steps program. Time is on your side. Slow and steady wins the race. Good Luck!
Congrats on the increase. I am not familar with how SDFCU operates. But in a years time with great payments and low Util reporting. You could get an unsecured card even better than Cap1. Barclays is inq sensitive. PenFed I think (dont quote me) is the same. They are a bit stricter than NFCU. Plus Barclays is a strange beast anyway. I'd go the Disco route after building some more down the line. For now let things age. The cards will be there down the road. Got to lay the bricks to get to it. Which you have done. No rush. Let the score rise some more. You got enough hits in 2018. 2019 let them age.
If it was me, I would keep the SDFCU secured card as long as possible.(like forever lol) From what I have read its not a terrible card and depending on your average trade lines and you not needing the secured deposit back, it may be worth it in my opinon to keep it open with your other older cards for the AA boost alone which accounts for I believe 15% based on credit history.
Thats a good reason, I dont think thats a bad reason either. But I believe our credit takes into count of our average long term age, not just our oldest.