Hello John and welcome to SMF, I take it you're from across the pond, me too but only in the other direction.
No we don't mind questions, we all have them, I'll try to give you some ideas on the ones you've asked.
Like has already been said, grilling and smoking are different so you will need to decide what style you want to use. Each one has their benefits, grilling is usually done in a short amount of time, whereas smoking can take hours. You can
smoke on a Weber Grill, I'd suggest a large grate model, so yes you could conceivably do both on one grill, another possibility would be to buy a grill and a smoker, Weber's Smokey Mountain smoker is used by a lot of people here, myself included with fantastic results, I also have a Weber Genesis E-310 that I use for grilling. You might try looking for a Frontier Pro, I think that's the name, they are sold from the UK and are an upright smoker like the WSM
For improvising a smoker you could look at the UDS thread here to get some ideas, they are simple to build, made from 55 gallon drums and don't require any welding.
The general rule for smoking wood is is any tree that bears fruit or nuts is good to smoke with, as to which one to recommend I'd be out in left field because we don't have any of your kind of trees here, may I suggest just trying different types and then you decide which you like the best.
I hope that helps a little,