1 as far as changing the read-only attribute on a file OR folder, right mouseclick on the file/folder, then leftclick on 'properties', then REMOVE the tick in the read-only tickbox, then click 'ok'
2 only with the original three sins races the others will NOT have the extra fleet/caps, to make a mealstrom version you would have to edit ALL of the RESEARCHSUBJECT_MAXCAPITALSHIPSrace#.ENTITY and RESEARCHSUBJECT_MAXSHIPSLOTSrace#.ENTITY files from mealstrom where race is the race it is for, and the # is the research level it is for and alter the lines near the bottom that read perLevelValuethat is two lines below the modifier type (eg CapitalShipMaxSlots or ShipMaxSlotLevel), and as a suggestion I would recommend having the extra limits mod as a separate mod that is stacked ABOVE the main mod and keep the original mod ORIGINAL.
3 as far as added planet mods, there is 7 deadly sins, solar sins(do not know if there is a diplomacy 1.31 version yet) distant stars, the old celestial bodies( do not know if there is a dip1.31 version yet), and from memory zombiesrus5 also has one.
harpo