I believe all of them can catch. And agree that they are not used enough. Their lack of production comes from lack of inginuity in the offensive game plan.
Both tight ends can catch. Problem is we rarely see them run routes. I've seen 3 very, very nice completions to the TE's this season up the seam, for good yardage, 2 to Jacobs and 1 to Clement, and I've seen 2 poorly thrown balls to Jacobs since. Our TE's mainly stay in and block, we need to get them more involved because that will soften their run defense. Also it wouldn't hurt to run a nice delay in that 2 tight formation, I bet we could get good yards up the gut.
I don't think the coaches are ready to trust the O-line to protect Mett sufficiently on their own. The tight ends are staying home by neccessity.