I did the oil and camshaft chains on my accord. A long story that I posted on this forum. Although I've not done the job with the engine in situ, and maybe it's possible if you have a ramp, I ended up realising it was much easier to take the engine out.
I have various tools and parts that might be useful to you to buy or borrow. The pulley holding tool, 3/4 breaker bar and 19mm socket, oil pump chain from an engine that had covered 86K miles, workshop manual ( for a Civic with the same N22A engine), maybe an oil pump chain tensioner in good shape, and the chain guides for both chains. Let me know if you need any of these.
Re the injectors, I wonder if it is essential to get them out if you are just changing the oil pump chain? I had absolute hell on earth trying to get the injectors out of a Civic engine I bought, and never succeeded. If they don't come out fairly easily, by wiggling and light tapping, you could be in for a huge problem. Also the injector clamp bolts can break off. But possibly the chain cover will come off with the rocker cover still on? Then, from memory, with the sump removed, you will have to get the crankshaft sprocket off, but there might be enough play in the cam chain to do that once it's slackened. With the engine out and the chain cover off you could set the timing perfectly to TDC and make sure the cam shafts don't move while you do the lower work? Just an idea I toyed with after spending hours and hours on my Civic engine injectors ... ie, was there a way around needing to get the rocker cover off? Others might comment and advise.
Good luck, Tim M