Yes WR is a need. McVay said, "It remains to be seen", regarding Reynolds filling Sammy's role. That is not a glowing show of confidence. Personally, I have my doubts about both, he and Thomas. Going from Watkins to either of them, is a huge step down.
OL is not the number 1 need. I don't draft first rounders to sit on the bench. OLB, WR, or even Safety could be the first the positions picked. Joyner is great and all but, they may be looking to find his replacement. Safeties are not getting paid. There are some good ones sitting at home right now. If they can find a young guy that can produce well enough, they may have to let Joyner walk next year, to save cap space. They had met with two Safeties that I know of during the off season. So they seem interested.
Kromer has been able to identify later round Offensive Lineman that he is able to develop into good players. I wouldn't be at all surprised if there are a few taken later. I would be surprised at an Olineman in round one though. But, anything can happen I guess