A plant's negative reaction to root disturbance can be due to a number of reasons. For some plants, root disturbance lays the plant's roots open to infection by soil borne pathogens that can kill the plant. (Proteas!) For others, a change in soil level can do it. This is because the oxygen level in the soil changes. Too much deeper and the roots don't get enough oxygen and they fail. For Abutilon which is a relatively thirsty plant it could be that the roots stop taking up moisture, or the top growth needs considerably more moisture than the disturbed roots can provide. In addition, the Abutilon root system is relatively large, so losing some of it is very stressful to the plant. What I do when transplanting just about anything is to provide temporary shade via a shade cloth covering a cylinder of wire fencing until the plant can once again take the level of hot California sunshine that it could previously handle. I try to get as much of the root ball as is physically possible. I keep the soil moist but not waterlogged. If the plant fails, well then...garden center retail therapy for the plant owner is advised. ;^)

The burned leaf tips and margins arte usually attributable to a drought response, triggered by over-watering, a high level of salts in the soil, and sometimes but not often - under-watering. The 2/3:1/3 you mentioned doesn't hold as much water as it would if you'd left the perlite out, but the ht of the perched water is the same with or w/o the perlite. This means there is a soggy layer of soil (100% saturated) at the bottom of the pot after you water. If you're watering when only the top inch or so is saturated, you're watering while the bottom of the pot is still saturated. This kills roots and causes lots of physiological problems related to drought stress and impaired metabolism- so the first thing I'd concentrate on is root health. Put directly, you simply can't have a healthy plant unless it's on a healthy root system. Wilting is an indication of drought stress, and not a particularly desirable condition for the plant. Still, it can be employed as a useful gauge re how long the plant CAN go between waterings. The occasional slight wilt is a stress, but it's preferable to the extreme stress of a forever soggy rhizosphere. Note the day you water and the day you see wilt. Count the days & start watering a day or two before you expect the plant to wilt. A sharpened wood dowel or skewer stuck deep into the pot is an excellent way to test for how wet/dry your plants are, too. BTW - not sure where you live, but when temps allow, your plant would much rather be outdoors. Al

I've grown flowering maples numerous times, typically as a summer annual as most are not winter hardy. Have even overwintered a few as a houseplant. They really do not require any more attention or care than most other annuals or seasonal plants. Personally, I would opt for more of a 5-1-1 mix rather than the gritty........abutilons seem to appreciate a consistently moist soil that is easier to monitor in the 5-1-1.

it appears to be a shrub.. that peeps also bring indoors for winter ... you might want to try the houseplant forum .... for other muses ... such plants .. indoors ... might be hard to bring to flower .. unless you can give it the light it needs for flower production ... how much light will it be getting?? watering can also be tricky indoors .... as well as humidity .... based on your winter heating ... does your pot have a drain hole? did you just transplant it??? frankly .. when i bring in zone appropriate plants for winter. ... all i hope to do.. is get it thru winter ... until i get it back outside late next spring ... if in fact they bloom.. its just all gravy ... i dont really hope for it ... and dont get bummed if they dont.. but do a happy dance if i get lucky ... ken https://www.thespruce.com/how-to-care-for-abutilon-plants-3976754