1. Full member can communicate with both full and limited members, and limited can only communicate with a full member(s).
2. Total number of partitions is 0x7fff (since MSB used as a membership flag: 0 = Limited, 1 = Full). On practice each port has a limitation for the number of partitions it can enforce. Most (older) HCAs handle 127 pkeys (or less?), so you will not be able to make a single host port be in more partitions than that number. Switch ports also have a limitation for number of pkeys it can cache in its tables (64 or more) but it doesn’t affect number of partitions you can have in the fabric.
3. Yes, it will be replaced. Please see 4036 manual at http://support.mellanox.com/ftp/Documents/Grid_Backbone_Switches/4XXX/Grid_Director_4000_Family_3.9.1_User_Manual_DOC-00…
More details on subnet manager, partition configuration and config file format can be found in OFED user manuals – for example:
http://www.mellanox.com/related-docs/prod_software/Mellanox_OFED_Linux_User_Manual_v2.1-1.0.0.pdf