Cheers mate!

Glad to help when I can.
First, my starting XI would be:
GK : Lehmann (Lloris after 1 year though)
DL : Clichy
DR : Sagna
DC : Gallas
DC : Richards
DM : Gilberto
CM : Fabregas
CM : Diaby/Pirlo
AML: Eduardo**
AMR: RVP
ST : Owen
** You asked about a left winger and Eduardo. Yeah, sell him as he's rubbish in the game. Your options are plenty here. Between Young & Giovinco, I'd definitely opt for Giovinco. Young is not good enough to be a starter at a big club. But better options that Giovinco (
imo) are Guardado & Menez (legend!). Menez especially. Just amazing players both of them. Marcelo is also great here. You can also look at Ben Arfa. He's very good but I prefer the other two. The best option is obviously Silva from Valencia. If you're lucky, he'd have signed a new contract with a 30M release clause there. He's WELL worth that money mate. Get him if you can for 30-35M. But if not him, I'd strongly recommend getting Jeremy Menez. Will slot into your first team easily and is awesome there too.
As for a striker to play second fiddle, you can actually get an Englishman here if you want. Jermaine Defoe is a good striker (gets plenty of goals), Arsenal is one of his favoured clubs AND he should be available cheap. If he's still at Tottenham, I dont think it should be a problem is you sign him (fan's wise I mean). They loved him when I got him in one of my games. Billy Sharp is another English striker who's pretty good. I'm not too much of a fan because of his poor passing but I've seen many people talk about him and he's regarded pretty high on these forums. He should be available cheap as well. I think both of these guys will be happy if you only game them a few games a season. But you dont necessarily need one here mate. You have Bendtner, RVP & Walcott who can all play upfront. Also, if you get Menez, he can play upfront too. So not really required and you should only get one if you have spare cash.
Now, one thing that you MUST stop right away is stop retraining Vela to AML. That kid turns out to be among the best strikers in the game. You have plenty of players who can play on the left wing. DONT ruin him, you'll come to regret it. I'd say send him on loan again for a season. When he comes back after that, give him some games here and there. Then he'll be more than ready to take over from Owen.
As for cheap wonderkids, I'd recommend buying Lulinha & Banega. They both turn out great. Banega can eventually take over from Pirlo is a few seasons and Lulinha becomes an AWESOME AMC. Get him tutored by Riquelme and Banega by Pirlo. Also, you might look at getting Michael Mancienne from Chelsea. He becomes a good, solid CB. And he's English which you like. Like I said last time, make sure you get Baxter in. He becomes great. Spend some cash on him if you have to and offer him a role as backup. He should sign for you then. Go to all clubs in the league and check their U18's out. All those that are regens, right click on them and choose approach to sign. When you do that, your assman will tell you if the player will be a "quality", "good", "decent" etc signing. If its good or quality, then just offer them a role as backup and sign them up. If its decent, get a scout report on him and see what they say. I ALWAYS do this every season and am able to pick up a few great regens. You'll find some wonderkids (future) this way.
As for the formation, if 4-3-2-1 works for you, then stick to it. I personally always like to play 2 striker upfront. After having Wenger frustrate me many times this season starting only Ade upfront I'm glad he's not started playing Eduardo more often. Cant wait for RVP to return!!

Anyway back on topic. If it works, then stick with it. But make sure you play Pirlo is big matches like Chelsea, Man Utd etc instead of Diaby. Other times, its your choice really.
Hope that helps you some.