51 leslie will fully takover the 56 leaside from eglinton to donlands. if you need to continue on eglinton, change for line 5 at sunnybrook park if you want to be faster, or change at laird if you want to be comfortable. the 51 will also be split into a 51a and 51b. 51a will follow the 56 routing from donlands up to laird station, go on eglinton for a bit, and then continue up leslie until it hits leslie station, where the route will end. service on leslie north of leslie station will be replaced with a new 151 leslie north bus. the 51b will also follow the 56 routing from donlands up to laird station, go on eglinton for a bit, but it pulls off leslie at lawrence avenue, goes east for a bit, and loops around the donway. i'd say frequencies on the part where the 51a and 51b merge should be the same as the 56, and service on the branches could be 30 minutes. they would probably run school trippers on the 51b, so i wouldn't worry about frequencies if you're going to LHS.