The good news is that roasting smoke smells wonderful while you're roasting. To some people it still smells wonderful two hours later, but to many of us it becomes stale and cloying. Hot-air poppers can be used on a porch or balcony in clement weather, or operated directly under a kitchen exhaust fan. Don't try to use them outside in temperatures under 50F however, since the cold may prevent them from achieving effective roast temperatures. Ovens that are components of kitchen ranges are well-vented and carry the smoke outside.
All coffees roast somewhat differently.
If you have been roasting one coffee regularly and you begin roasting another, do not expect it to behave exactly like the first. The separate batches of beans from differing origins that together make upmost blends can be combined before or after roasting. If the batches are combined before roasting the look of the roast may not be absolutely uniform, but the cup quality usually will be fine. The only situation in which two components must be roasted separately is in the case of blends of decaffeinated and regular beans, since decaffeinated beans roast much more quickly than untreated beans. A methodical approach is definitely the best way to achieve intimate knowledge of roast and coffee taste.