"B-List" Invites....or second round invites

I realize that this is a rightfully touchy subject, so if you're reading, here's my explanation: my husband and I live in the UK & were married last August in London in a small civil ceremony, due in part to having visa issues. I wanted to have another ceremony & reception in DC, which we are having on May 25th (39 days!). My husband is Belgian/South African, I'm American. Our friends and family are literally all over the world- Australia, South Africa, the Middle East, Europe and all across the US. I sent out save the dates and invites super early, but as the date nears, we have understandably had many people decline. There are some people I wanted to invite but held off on doing so because I didn't want to breathe down peoples necks for a yes or no answer, especially as many don't live in the US. Is there any tactful way to invite some more people? Or is it just downright rude? We never had an A or B list, just had to prioritize family and old friends. Thanks for reading