As someone else pointed out, you have sold Ox, Coquelin, Gabriel and Gibbs this season, with only Kolasinac and Lacazette coming in. Surely those players / positions need to be sorted first before splashing on another striker and a winger?
Gabriel was sold because we have Koscielny, Mustafi, Monreal, Mertesacker, Chambers and Holding. Mertesacker will retire at the end of the year, but we bought a 20yo CB just last week. So we've got 7 senior CBs currently on the books, one too many at least, Gabriel never needed replacing by any stretch of the imagination.
The Ox had no place in our team, he was only able to get starts at wingback. He wasn't productive enough in the forward line, and Wilshere came back from loan and pushed him down one more spot in the midfield pecking order. Looks like the Liverpool move was good for him now that they've sold Coutinho, so win win really.
Coquelin was barely playing, he had Xhaka, Elneny, Ramsey and Wilshere all in front of him, and lets face it, he's just not good enough, that stellar 6 month period a couple of years ago aside. With Iwobi capable in midfield and Willock coming through, we've probably got just enough there, but could probably take a look at it in the off season.
At left back, Gibbs was sold, Kolasinac was bought in as a direct replacement, and Maitland-Niles has now emerged from the youth team. Still got Monreal as well. Definitely no one required there.
So for me, we don't need to replace any of them at all. If we do buy any midfielders or defenders, then we will need to sell further players to accommodate them.
The forward line is where we've needed improvement, we haven't been scoring nearly enough. And with Sanchez and Walcott going, we are lacking in personnel now too. We definitely need at least one forward.
Also, despite the riches at our disposal 2/3 seasons ago, I feel goalkeeper is fast becoming a priority. Cech is declining and Ospina doesn't command the box at the set piece well enough for english football. Did we insert a buy back clause in Szczesny's contract??? I'd love to know what happened there. After the smoking in the dressing room incident, Wenger basically cut him loose, and that was that. He was loaned, then sold, and his performances at Roma were never taken into account during that decision-making. Can only assume it was 100% down to attitude. Very sad though, I loved him.