Despite all the efforts, I couldn't manage to insert both side screws for the antenna plate. I ended up only using a single one (the one nearest to the HD connector), hoping it will hold the weight of the SSD.
As others here, the second time I replaced the internal drive I didn't disconnect the ribbon cable from the logic board. I was installing an SSD, so maybe it was a little easier than with an HD. However, I don't remember disconnecting and reconnecting the ribbon cable to be an issue.
