Construction will start soon. I worked on a clubhouse remodel for an apartment complex (through my part time job, not my own business).

That would depend if the items are readily available / in stock. You could probably wing it if everything is in stock, but often things can get delayed, or there's a mishap with delivery or something arrives damaged and you need a replacement. Is everything being delivered to a warehouse? It is a pretty tight schedule unless you are on top of it. You'll need to track shipments daily to catch any issues should they arise. Also scheduling an install day / movers ahead of time as people's schedules get booked up or are closed off around the holidays. In your furniture selection process, you'll just need to verify the lead time and stock with the vendor and avoid anything that could have a potential long lead time. Avoid things that may take up to 2 - 3 weeks, it could end up being longer. That, or the client will just need to accept some items may be delayed and they'll have to wait until after the holidays for a 2nd delivery for any late items.

To add, I've done a lot of staged model units where I'm selecting stuff that is either in stock or has a short lead time. I typically give myself about 6-8 weeks to make sure everything is received at a warehouse and then schedule one installation day.

I use photoshop to play with paint colors. it can be tedious depending how clean / cluttered the photo is.

It would be best if you or someone from your team is on site to facilitate. While the installers can refer to your furniture plans, depending who you hire, they may or may not place accurately or with care. I've dealt with a lot of different warehouses, and they've been hit or miss. There could be items that end up having some damages that were missed during receiving or break on site, so it's just good to be able to be present and manage. Things seem to go a lot smoother if someone from the actual team is there, and you're able to know firsthand if anything is wrong so you know how to inform the client and if you need to contact your vendor for replacements, etc. I usually deal with a ton of small accessories as well, and it's just a lot easier to be on site if anything is missing as well. Sometimes the warehouse can forget to bring something - a lot can go wrong even if you plan it well and inform the warehouse of everything you need pulled.