I'll let someone else address connection times in Washington DC... as I live in a capital city many thousands of miles from there. and REALLY lack the local knowledge required!..
Suffice to say if you booked it all on one ticket then you have far, far less to worry about....
I'll assume that IS the case ... and we'll start at the very beginning... (why did the theme from "The Sound of Music" just pop into my head?
)
Liquids. If they are packed in the bags you plan to check then there is no problem with any of the stuff you mention... except that liquids can add up weight wise.. and to avoid extra charges you want to keep the bag(s) within the allowance granted by the particular airline...
When you arrive at the Kansas City Airport you need to check in at the desks operated by the airline you are flying... your bags will be checked through to your final destination.. you don't need to worry about them in transit. (see assumption above about ONE ticket)
You will also be issued your Boarding pass(es) for the flight(s)... This/These should have gate info on them but it doesn't hurt to specifically ask if you feel the need... If the BP for the second flight doesn't have gate info (gates can change/may not have been allocated that early etc) -
don't sweat it - when you arrive in DC just find the flight number (which really should be on the second BP) on the monitors and look for the gate # there .... You can "practise" that at Kansas City before your first flight... they are all pretty similar..
If you can't get both BP's then ASK the check in folks what you are meant to do.... there is NO SUCH THING as a stupid question.. and those folks have dealt with first time flyers before....
Sorry if that was
too basic....
EDIT!....[B]WOW.. I clearly type too slow!!!![/B]