A good selection and quite similar to my 8. Think your problem is their levels. Well done for getting this far but they need to be stronger now.
If you are saving your vr DNA for Indominus then remember you need 50 rex DNA as well for each attempt. May be time to upgrade your vr
One of my favourite openers is stegocetatops get that higher.
I think you have a good team. I wouldn’t really switch any of those for the others you have, just level them up as someone said above. The rest is just patience (you will lose lots of fights because battles are getting harder) and good tactics, but my team is not much better than yours and I managed to join arena 7, so just level them up and be patient!