Did you properly ground yourself to the case before putting the spudger to the connector/logic board? Did you use a spudger or something else that is non conductive...or did you use a flat blade metal screw driver instead and compound your error by not grounding yourself before touching the logic board? All kinds of variables here but the bottom line is iFixit provided you a guide to fix your computer. Lots of others have followed this guide without trouble. Your battery issues are not their fault. They did say this guide was moderate difficulty...maybe it's just a little beyond your skill level. We should all know our limits!
Sooo the track pad is under the battery...you kind of have to remove it to get to the track pad.
Not sure which screw you are referring to. Every screw that needed to be removed seemed to be clearly identified to me. Instructions and pictures were clear and I was able to complete this job in about 30 minutes. That included the time I took to replace the feet while I had the lower case removed for the trackpad job