1) Paul got the sounds spot on, 'comb' sounds like 'foam' (or 'home' or 'Rome'), whereas 'bomb' sounds like 'Tom'.
2) Convey is generally pronounced in the way that the dictionary says, however, if the speaker wanted to emphasise the word, the letter 'o' would be pronounced quite clearly.
3) If the sentence ends in the word 'friend', the letter 'd' is pronounced fairly strongly. If there's another word after it, it can sound soft, particularly if the following word starts with the letter 'i'.
4) It's pronounced 'əˈɡriː', the start sounds like 'uh'.
5) Yes, I always pronounce the 't', but it can often sound very soft so it can be difficult for non-native speakers to pick up on it at times.
6) The difference in pronunciation would be regional, on a personal note, I tend to say 'askt'.
7) This one is probably my fault, haha, in London (especially North London as Imanuela pointed out), the 'g' at the end of words like 'thing' can often sound like 'thingk'. Most people will probably say 'nothin', but occasionally in London you will hear it ending with a 'k' sound.
In Essex/Cockney accents, 'name' can sound very different to standard English, so I understand where you're coming from. I think the sound is more like 'naime' with a hard 'n' sound followed by an 'a' sound that goes up. It's hard to explain, I can try and show you.