The sweet spot in this draft is in the 50 to 100 range, accumulating extra picks in the late 2nd to early 4th is extremely doable and should be the Eagles goal.
Unless someone completely unexpected drops to the late 20s the Eagles should absolutely trade back. There is max 12 guys that have first round grades and then a lot of "who do you prefer" for the next 80 or so. Throw in the fact that there will be QBs drafted too high and a bunch of head scratching picks and you've got a high probability of landing a bunch of guys with the 62, 75, 84,, 93rd, etc picks that you may have considered at 39.
Other teams know this as well, but fortunately for the Eagles this is also a draft where there may be a few teams targeting Day 2 QBs which may give the Eagles opportunities to trade down more than once and accumulate 2 or 3 extra picks in this range if they choose to adopt this strategy. This doesn't happen a lot but this year may pose a unique opportunity to do so. I would be more than ok with them dropping down once to give a team a jump on the Day 2 guys at 32, and then dropping back again and making their first pick in the 60s if they could come away with 2 or 3 extra picks before 110 or so. Draft capital charts indicate this possibility, but you have to have 2 to tango - again, the day 2 QBs may make that an opportunity.