I also skipped all the additional disassembly. I used cards and wire to cut through the adhesive quite easily. I also did not apply any tape on the new battery. The Mid-2014 laptop seems slim and tight enough to keep the cells from moving and the two screws at the power connector area seem to stabilize the connection and battery as a whole. Such STRONG tape seems unwarranted for the amount of squirm room in such a tight compartment.
P.S. Remember, while you have it open, clean, clean, clean!!!
No hard drive icon usually means you forgot to reconnect the hard drive cable connector back to the main board, or if you didn't disconnect it in the first place, then in wiggling with the hard drive, you popped the other end of the connector off...that's what I did :) .
Don't forget to reconnect this connector. Otherwise you'll get the question marked folder blinking on your screen.
First I released the plastic top. Then I removed the touch pad connector. With that, I was able to shift the top case down a inch so the power connector was exposed. I pressed a small screw driver along the middle on the long side of the power connector and twisted back and forth so it would wedge the connector from the socket. I left the speaker(long wires) wires connected and just flipped the case off to the left.
I left the DC board alone screws, cable and all for my hard drive swap.