RE: the players mentioned by OP

I just hope they tag Allen Robinson if they can't get a deal done. That's the only FA move I'm really worried about. 

- Pugh would be nice - but he's trying to get Osemele money.  Maybe Coughlin can play a role in convincing him to come here cheaper, but I don't know if that's the best way to stretch the limited cap space right now. 
There will be a quality guard late in the second (or a really good guard late in the first if you aren't adverse to that.)

- I'd go nowhere near Jimmy Graham. He's a red-zone target and that's basically it. He does nothing else well enough to command the money he'll get.

 - I'd replace Colvin by drafting a mid-round DB and throwing him into competition with Patmon and Myrick. If you're going to pay a guy too much money to play the nickel, just pay Colvin. He's younger and knows the defense. 

 - I think the 2019 draft is the place to address the safety position. Not 2018 free agency. Let that one ride for a year as is. Not broken... don't fix it. 

 - Omameh makes lots of sense to re-sign if they can agree on a reasonable contract.

---

My FA class this offseason is:

 - A-Rob
 
- Colvin (if the price is friendly - not likely to happen)
 
- Omameh (again for a fair or friendly price) 

 - Crockett Gilmore was my TE choice here, but he's changing positions due to knee issues, so:
Trey Burton would be worth a look if he doesn't break the bank. 

 - I'd also take a long look at scouting reports on the FA guards and Centers hitting FA.
There are a bunch of centers about to hit year 5 in the league. A couple of them may represent an upgrade at RG if they have the versatility. One of those dudes might be had at mid-tier money and present good comp. in camp.

---