1. ITR : 1 missing ITR shouldnt be a prob. Plus all your other finance related stuff is in place (loan etc)
2. lived abroad : If I understood your question correctly, you have ticked 'No' to the question - have you lived abroad for more than 6 months. If thats the case, this is a serious mistake. but you have also specified that the country was UK in the space provided ? then depending on the VO, he may choose to overlook this mistake.
dont want to scare you, but this could amount to declaring wrong info. if you have explained the country, period etc, then u cud squeeze thru. pray !!!
3. IELTS date : This is no big deal. they should be bothered about whether you have taken the IELTS etc. i know many ppl who ddnt even state anything abt the IELTS in the SOP and got the visa. so chill !