Without recommending any particular printer or maker, I can make a few suggestions. For the simpler monochrome jobs, I'd go with a laser printer. Relatively cheap operating costs (especially if you buy third-party toner cartridges) and very good quality prints. Many do very well even with grey-scale photo printing. Basic resolution is 300 dpi, but many come at 600 dpi minimum just to start. I use mine to print the return address / letterhead on the envelope front, too, so no costs for pre-printed envelopes, or even letters IF your letterhead is monochome also. For this one, look for one that has an easy way to print envelopes if you want to do that. Almost all can do some of this. But the colour laser I use now can only do that by feeding one at a time through a general-purpose manual chute in the front, and it takes at least 45 sec per envelope, so printing many in one run ties up a person for a while. My older HP LaserJet (it finally failed) used to have a small chute system built into the opening for feeding a small stack of various-size paper, and I could load 15 to 20 envelopes in there and just let it run them all through. If you print a lot, look for a printer that comes with (or can be fitted with at extra cost) a large main paper feed tray. Also consider one that has a permanently-attached second feed tray for envelopes if you want to do a lot of those without running to the printer to stick them in.
I agree with your thinking about a second unit. If you plan to do colour higher-quality prints, a combo printer / scanner with good scanner resolution is a good idea. My colour laser by Lexmark does a very good job of colour photo printing, but it does not include a scanner. It does well for common colour business documents and presentation hand-outs, but it can NOT print on high-gloss photo paper. However, a colour laser printer is more expensive for operating costs, even with generic toner carts. But for really high colour prints especially on glossy or matte heavier papers, go with an inkjet unit. For glossy photos, use the specific paper recommended for that printer. The ink and the paper need to be matched, and how to do that is tough when the makers don't tell you the detailed specs. I do not recommend the cheaper units that use a single three-colour ink cartridge. To get good full colours you need the four-colour ink system (Cyan, Magenta, Yellow and Black or CMYK) with at least the Black cartridge (used much more) separate so it can be replaced by itself when empty. Some fancier printers offer six or more ink colours (by adding lighter-coloured versions of the three primary colours) but these are for extra-high quality photo prints that require accurate reproduction of intermediate colours, and are not usually required in business uses. Regarding resolution, 300 dpi is minimum, many will do 600 dpi easily, and you likely do not need higher than that.
In the old HP inkjet unit I have, the Black and three-colour ink cartridges the two are separate) each also contain the -print head. This has the advantage that, evey time you replace the cart, you get a new clean rpnt head. Also, even if your ink has not run out, replacing a print head that is clogged is easy. However, that measn every new ink cart is a bit more expensive than other systems. To some extent I reduce that cost by refilling the cartridge with a third-party ink kit, but that consumes time (and money). Other printer designs have the print head and the ink cartridges separate so the ink carts are cheaper and the heads last through many ink changes.
Check very carefully if you are thinking of using third-party ink cartridges. Most printer makers now include some chip in each ink cartridge and software in the printer to ensure that you only install new carts made by the printer company. Usually this is tied into the way the printer tracks the ink level remaining in the cartridge. In some cases there MAY be a way to defeat this, but of course the printer maker then would tell you that voids their warranty. For example, I had a Canon printer /scanner for years for which I bought lower-cost ink cartridges from a third-party supplier and the carts included their own properly-reset chip so that the printer believed it had an acceptable full new cartridge installed. On the other hand, I have an old Epson dedicated 4" x 6" photo printer (excellent prints, by the way) for which there are NO third-party ink cartidges, and I always stuck to genuine Epson inks and photo papers for that one.
For the Scanner part I agree you'd want that with full colour ability, so getting that in a colour printer is best. Watch out for the resolution statement on these. They all include some software tools in the printer / scanner unit that can boost the apparent resolution a lot by interpolating between the actual scanned dots. So they'll tell you the max resolution is, say, 4800 dpi. But what you really should look for is the HARDWARE resolution - that is, the dpi actually generated in the scanning mechanism with NO software enhancement. 300 dpi is reasonably good, 600 dpi definitely is better. Higher than that usually is needed only if you are doing high-detail scans for commercial photo and advertising work. Virtually all printer / scanner units today include a TWAIN compatible printer device driver. So any graphics software package you use can treat the scanner as an input device, and that driver actually includes a few basic features like cropping, colour detail and resolution, and brightness / contrast adjustments. Some of those are best done AFTER the scan in your main software, but the scanner driver's tools are useful anyway.
3-in-1 printers do printing, scanning, and copying and are common. All-in-One (aka 4-in-1) units add ability to send and receive FAXes if your office uses them and wants an added FAX machine. Personally, I find that somewhat useful this way. If I generate a document in a word processor or graphics package, print it out, then run it through a FAX machine to send, it gets slightly distorted and acquires extra dots and smudges. But if you "print" that document right from the software to the FA X machine (that is, the FAX system in your printer) that Windows can treat as just another type of "printer" available to you, the document that arrives is completely clean and clear because the computer does all the conversion of image into FAX dots and no "noise" gets added to the transmitted image. You should decide whether either copying or FAXing features are of any use to you in a colour printer / scanner.