The standard rooms at all 3 of those hotels are actually pretty small. Out of the 3, I like the location of the Ren the best, but those are like 210 sqft rooms. Lexington is new & nice rooms - but wouldn't want to be on the east side in that neighborhood for 7 days for tourist reasons.

Have you checked the Residence Inn Central Park or the Residence Inn Times Square - much easier access to subway lines around the city, free breakfast daily, larger rooms (at the RI Times Square anyways). For Cat 8 hotels, I like the RI Central Park better - great views, strong location from an accessibility perspective, good free breakfast daily, etc.

Also, another good option may be Brooklyn Marriott - I think it's an 8 as well - not in Manhattan proper, but easily accessible to lower Manhattan & the sites there - anywhere in the city is 20-25 minutes max by subway (and buy a weekly card - taxis/Uber will get expensive!)