All speakers will work with a typical four channel amp, though you may want to check the wattage before you pair it with some speakers.
The Audiobahn A2200HCT 2-Channel Car Amplifier is a good choice.
A 4 channel will work for your door speakers. But the idea setup would be a 5 channel 4 for your doors. Then have 1 channel for a sub.
No that would be a 2 channel amp. 1 speaker per channel. 2 speakers= 2 channels 4 speakers= 4 channels
a channel refers to the speakers or subs. for example a 2 channel amp can power 2 subs or speakers. a 4 channel will power 4.
It depends on the application. If you have an amp that is stable in 8 ohms per channel, then 8 ohm speakers will work best. However, if you wanted multiple speakers on that channel you could use two 16 ohm speakers.
Use 1 channel for fronts & the other channel for the rears.
You can connect a sub and speakers to one amp, depending on how many channels your amp has. A 4 channel amp will be able to run one (or two) subs using two channels (one bridged* sub or two subs) and two speakers running one channel each. A 2 channel amp will run 2 speakers or one bridged sub. A 6 channel amp will run one bridged sub (or two subs), 2 front speakers and 2 rear speakers. In my opinion, you will get the most performance, depending on which amps you use, by using a monoblock amp for your sub and an amp with enough channels to run all of your speakers. # Bridged = putting together the power of two channels to run one sub or speaker. Note: not all amps are bridgeable.
Monoblock amp? No. Only 1 channel which is good for one speaker, or one sub. What you need is either a 2 channel amp or a bridgeable 4 channel amp, which would be overkill anyway. If the amp you have is 2 channel, it would be ideal.
Yup
Hook your speakers up to the amp.
200 RMS 4 channel or 2 channel so u know add the rms of the speakers to find the amp rms needed
There MUST be some sort of amp powering the sub. An amp gives you power much like if you plug a light into a wall outlet. Hopefully there is a second 4-channel amp powering the speakers... Also, are you listing rms or max power for the 4" and 6x9" speakers? What sort of power is being run to the speakers also? Your question needs to be more specific to be able to answer it properly.