In my opinion hodl and buy would be the best strategy, because ends of year are always bullish.
Last year's end wasn't bullish at all. A lot of longs were crushed when we fell from $6000 to $3000 while people expected a bull run. I get where you are coming from where usually, seasonality kicks in in the fourth quarter, but it seems that the market had other plans last year. I was expecting the price to go up too and paid the price for it. 
Then diversify a little in the altcoin markets next year and wait the next mega bull run that should happens in the year 2021.
I would only consider going long on altcoins when they have consistently been indicating that the trend has actually changed. Right now that is not the case so I rather don't touch any. People have been trapped two or three times now with the altcoin pumps thinking altcoin season started.