Garden the cards you have now basically means, take care of them and let them grow, like you would a garden. lol Like the FICO forums terminology? It means pay them on time, try got credit line increases (not with FP and slim with Orchard), let them get older...all while not applying for anything new.
I think you are ok on inquiries. Inquiries remain on your reports for two years but are only factored into your score for one year.
Usually when you pull your reports (depending on where) it says you are currently opted out. But you can go here to either opt in or out....
https://www.optoutprescreen.com/?rf=t
If you are opted out you will not receive offers no matter how high your score goes.
And if the OC (original creditor) agrees to a PFD they can remove the CO, but it removes the entire account, not just the notation of the CO.
Wellllll, I personally have never had a Cap1 card. BUT, from reading posts here it's a hit or miss with increases from them. Might want to try a search for Cap1 CLI and see what you find. I know they have "levels" of cards and some get increases while some don't. I think it might also depend on how use the card. If you barely use it they may not be inclinded to offer you an CLI. You could also start another post on the credit card boards asking about people's experiences with Cap1 and increases???
But yes, "water" your garden! 
