I had the same thing happen regarding not being able to delete a strength exercise when I tried it out just now. I will report the issue to our developers. Thanks for letting us know!
I will turn in your request about support decimal points in the weight amount. I'm not sure if that change will be made; but, I will let the team know of your interest. Also, just so you know, I understand if you want the decimal information for your records; but, the weight does not make a difference in the amount of estimated calories burned.
Have a good evening!