Put only Mopar original mounts for the engine. Also have a look at your gear mount while at it, as that might also need replacement and it will save you some money to get both done at the same time
Try hitting the dashboard and the plastics around the key when you’re trying to start it. As far as I know the power for the immobiliser comes from either the wiper switch or the light switch and the wire may be loose. Might not work but it’s worth a go.