The house I am renovating in Zone 5 Central NY has a central core with the kitchen, guest bathroom and laundry room directly adjacent to each other.  I would like to minimize roof penetrations and keep my mechanical systems relatively straight forward. 

Will there be any issues with connecting the air coming from the filtered kitchen hood exhaust fan into a multiport system serving the laundry room and bathroom? 

What are the rules of thumb regarding duct length or other factors for determining when it is more efficient to consider discrete fans rather than a multiport system?  The reason for this question is that the current design calls for two separate fans in the basement with the exhaust punched through the wall and a fan for the master bath with the exhaust through the wall.  These locations would require 30+ ft duct runs with several 90s to connect to the core system for the laundry room/guest bath/kitchen.

What are good brands to look for for multiport systems?  Most of the references I have found on this site are 5+ years old.