I don't think the Ravens should sign any ILB on the market other than Ellerbe. The whole point of bringing him back is to ensure continuity and stability at the ILB position. They should put every effort into working something out with him, but if not, they'll just prioritize ILB to a higher degree in the draft.
Bynes played well in limited action last year and if McClain's health checks out, I think the team will expect a bounce back year from him with better DL play up front. They are GOING to draft at least one athletic ILB prospect this year and give them every opportunity to win a starting job. Plenty of ILBs drafted in the middle rounds have contributed starters' or near-starters' snaps in their rookie years (Sean Lee, Daryl Washington, etc.) and I just don't see the point in going out and spending money on anybody but Ellerbe.
Best case scenario is Ellerbe next to Khaseem Greene, Arthur Brown, Alec Ogletree, etc. If they can't bring Ellerbe back at a good price, just take that money and get better elsewhere, like at DT/NT, get an athletic guy who can cover and will learn the defense quickly in the draft, and hope you can figure out the position in training camp.
I think you are right that the Giants are probably the best fit for him. If he is part of a top 4-3 d-line he really has all the tools needed to succeed.
For what its worth, Peter King thinks Ellerbe is gonna be too expensive for the Ravens.
Whether in the draft or free agency, the Ravens need to get more athletic on the DL. You don't want your linemen playing too many snaps but they need to be able to handle it if required. They have too many bloated guys out there putting too much stress on their lower bodies right now. Every one of Ngata, Cody, Art Jones, and McPhee has had knee/ankle/thigh injuries over their college and NFL careers. All but Cody have also bulked up lately--Ngata has got to be over 350 right now and should be closer to 320, Art Jones was 290 in college but listed at 315 now, and McPhee apparently played most of the year close to 300 pounds.
shockingly, I can now see that the Ravens may not retain a single free agent of their own, apart from Flacco...
Ellerbe and Kruger seem to be pricing themselves out. Kruger will get it, not so sure if Ellerbe will
BMac could end up back here, but he's really a bottom of the pile type guy (not much upside, not much money) and will probably look for every dollar he can get
Reed, who knows what the deal is with him
Cary Williams has never even been mentioned as a potential stay. I think Ravens want to put Jimmy Smith and Corey Graham into bigger roles, and assume Webb will be healthy.
Did I miss any?
I don't think Ozzie sits pat and says "I'll take my 11 draft picks and build a kingdom". He's going to have to use free agency to add some pieces, and those are going to offset our losses in the comp pick formula.