Hi there,
Glad to see your getting back into the game, deathwatch are a cool and interesting choice to go with and can be very good on the tabletop in the right hands.
Whilst the advice above is certainly good it maybe aimed a little on the competitive side, one of the reasons I really like the deathwatch is the amount of character and individuality you can put into the models and the variety of options that can go into the different squads.
So I think before offering advice I'd like to know how competitive are you aiming to be? Do you want the list to be able to play at home with some good friends, take down the local
FLGS for some pickup games or are you looking to rock it hard in the tournament scene?
Having a list that suits the environment you will be playing in will go along way to making sure both you and your opponents have a good time with the game, the difference between a tuned tournament list and somebody just using the models they brought because they liked the look of them can be vast, neither is the wrong way to play but they don't mesh well.
Also is there anything that you really want to use in the list or anything in the army that is a no-go for you for some reason, I for instance love dreadnoughts so you will always see me rocking a couple :-)
Do you already have the models you have listed, are you willing/able to pick up more? Would you be happy to buy forgeworld options?
Ok, gonna help you out here because this list is very bad.
You need CPs so you are gonna wanna go with a battalion.
I guess you can keep the librarian if you want but a watchmaster or watch captain is mandatory for the re-rolls 1's.
Kill team squads should be:
1 terminator base gear
1 vangard vet so you can fall back from combat and still shoot.
1 black shield
sergeant with storm bolter and storm shield
4-5 guys with storm shield and storm bolter, that's it.
This load out is cheap and will do massive amounts of damage with hellfire rounds.
Take 3 or these squads around 180 points ea your 2 characters and some anti-tank. Maybe ally in a cheap warglaive.
Hope this helps.
Whilst this is indeed the current flavour of the month basis of tournament deathwatch lists it is by no means the only way they can be used and may be far from suitable for you depending on how you want to play as it uses very few of the models you had listed. You have a good idea of how to play your force and why the different units are there, this suggested list is all about maximum efficiency but doesn't contain may different options so may not be what you are looking for in deathwatch.