Lets take each of your problems one at a time;
H. Johnson...Johnson is a guard...but he can also play RT if you have that need....that makes him valuable!
"One of the most physically imposing players in college football, Johnson is a tremendous physical specimen. The biggest player to ever wear the purple and gold, Johnson started the final 38 games he appeared in, lining up at right offensive guard in three of those contests before taking over left guard duties. Despite his massive frame and considerable bulk, Johnson is surprisingly light on his feet, registering 16 down field blocks over the past two seasons. He shows very good mechanics for a player of his size and his road grading ability could see him shift to offensive tackle in the NFL, as he also has performed at right tackle during the earlier stages of his career with the Tigers."
For a player of his size, Johnson flashes decent knee bend, as his feet get out in front of his body properly playing in the short area (will lose balance running long distances, though). When he stays on his feet, he generates a good kick to his slide, and he can ride the defender off the play when he plays flat-footed. He keeps his head on a swivel and is able to pick up stunts, but gets in trouble when he lunges, which causes him to lose his balance and end up on the ground. He makes good contact in the trenches, but on the move, he will sometimes extend to far and lose his balance. He will also get off-balance a bit when working outside off the edge, but can pick up stunts late. When he tires on the field, he will revert to leaning into the defender or overextending to try to keep them at bay, but he will then lose power in his punch, allowing the opponent to slip off his glancing blows. While he is prone to overextending more than a position coach would like, he will generally play on his feet. He does not get beaten by the pass rush often, as he does show good foot quickness to recover (allowed just 3.5 sacks during the last two years as a starter, encompassing 815 pass plays).
Now lets look at Ramses Barden;
"Scouts who hadn't seen Barden play until his Mustangs took on annual Big Ten contender Wisconsin in Madison late in 2008 were pleasantly surprised by his skills. He has won numerous All-American and all-conference accolades, but production at the FCS level (122 catches for 2,724 yards - a 21.9-yard average - and 36 touchdowns the past two seasons) does not always translate to NFL success. But he proved himself more than just a tall jump-ball threat against the Badgers, and teams took notice. If he's not a first-day pick, his name should be called early Sunday morning."
Not only have the Dolphins interviewed him but they also have brought him in....if you remember....Parcells had a large receiver that compares to Barden...K. Johnson. If you have read the papers...K. Johnson has said "he knows what kind of receiver the Dolphins want in this draft."
Conner Barwin;
Barwin has more potential than any linebacker in this draft....but he also has what Parcells likes in his players, Size...Speed and agility.
Jasper Brinkley;
Brinkley is coming off a injury that happened in 2007;
"Missed all but four games of the 2007 season after tearing his ACL. … Underwent surgery September 2007 and wasn't the same player in 2008, when his athleticism was nowhere close to what it was pre-injury."
Sean Smith;
If you take the time to look at the combine stats between Smith and the so-called top Corners...you'll see that Smith is as equal as one player can be;
Sean Smith....10yd....1.53, shuttle...4.15....cone...6.92
D. Butler....10yd....1.46, shuttle....4.18....cone...6.84
M. Jenkins...10yd...1.47,...shuttle....4.08....cone...6.59
V. Davis....10yd...1.47,....shuttle....4.07....cone...6.75
My guess is that there's little chance for the Dolphins to acquire Jenkins...I would assume Davis would be off the Dolphins board due to his attitude problem...but even with that...no other corner is as large...or can out jump Smith. With the problem of larger and larger receivers...the day of 5'9" or 5'10" corners is coming to a end....they simply can't cover the receivers in the red zone.
I have done a draft as I believe that Parcells will...not by saying I want this guy...or that guy...but comparing who I find most likely will be available when the Dolphins select. It will change...many times between now and draft day...different picks the Dolphins will pick up...or if the case players...will effect any draft.
This is as good a player rating page as I can find...it's done well and I hope it helps all.
http://www.cbssports.com/nfl/draft/prospectrankings