They're all lovely names.
Kate - I love the simple but strong sound. I know a young Katie but haven't met any other young Kate/Catherines.
Ava - it's a nice name but there are a lot of Avas around - babies, children and teenagers - as it's been a popular name for many years now. I've also met a few young Adas recently.
Isla - love this name, and have done ever since I met my first Isla - in the mid 90s (she would have been born late 70s). But it has gone from being a rare name to massively popular and that would put me off. Iona, Orla, Eilidh, Ida have similar sounds/vibe and are less common.
Ruby - I like it but don't love it. Maybe feels a bit dated already.
Maeve - another I've loved since childhood, when I went to school with one. Was rare then, not so now but hasn't become as ubiquitous like Ava and Isla. I have only met one baby Maeve but several Otises - so I do associate it slightly with the Sex Education character now unfortunately but am sure that will diminish over time.