Don't think much difference in relative seniority on any of the fleets in EWR for new hires... Biggest issue is if you get 756 or 76T you'll not get to touch the yoke much and will be bunkie except for rare flights while on reserve or bottom line holder... I'd recommend bidding a 737 or 320 based on what lateral base you want next... If IAH don't bid 737... Other bases should be fine.