Don't let that put you off. Lots and lots of dogs are called Toby but it's still a popular and pleasant boys name. And Jake!
I've never seen that spelling of Frida. Only ever seen it spelt Freda so it may be one open to being misspelt. But hey, I've got a Catherine and people regularly spell it wrong. Either they miss out the 'e' or they start it with a 'k' (that's probably my fault as she's known as Kitty, but still!)
Greta just sounds like she's elegant and beautiful. But hey, just go with your instinct. None are awful or sound made up.