I can help you to connect esp as hardware serial for uno, nano and mega
chech which firmware is installed on your esp. If it is not v22 reflash it with v22 .there are many tools and instruction for that. once you do it I will further guide you.If you have problem reflashing let me know?
Read this thread for the detailshttp://community.blynk.cc/t/solved-failed-to-disable-echo-problem/3955
I used the four address tool and 4 bin files as recommended on this thread
important thing for reflashing make GPIO0 ground and CH_PD high .leave GPIO 2 floating .you may need to disconnect ph_d from high and reconnect to start uploading process.After reflashing remove GPIO 0 from ground and issue AT commands to connect your esp to wifi. also change baud rate to 9600.You have to leave ch_PD high for all time.